Answer:
Step-by-step explanation:
Evaluate the expression: 3c - 6d where c = 7 and d = -4
Answer:
45
Step-by-step explanation:
(3)(7)−(6)(−4)
=21−(6)(−4)
=21−(−24)
=45
Blair & Rosen, Inc. (B&R), is a brokerage firm that specializes in investment portfolios designed to meet the specific risk tolerances of its clients. A client who contacted B&R this past week has a maximum of $85,000 to invest. B&R's investment advisor decides to recommend a portfolio consisting of two investment funds: an Internet fund and a Blue Chip fund. The Internet fund has a projected annual return of 9%, whereas the Blue Chip fund has a projected annual return of 8%. The investment advisor requires that at most $55,000 of the client's funds should be invested in the Internet fund. B&R services include a risk rating for each investment alternative. The Internet fund, which is the more risky of the two investment alternatives, has a risk rating of 6 per thousand dollars invested. The Blue Chip fund has a risk rating of 4 per thousand dollars invested. For example, if $10,000 is invested in each of the two investment funds, B&R's risk rating for the portfolio would be
6(10) + 4(10) = 100.
Finally, B&R developed a questionnaire to measure each client's risk tolerance. Based on the responses, each client is classified as a conservative, moderate, or aggressive investor. Suppose that the questionnaire results classified the current client as a moderate investor. B&R recommends that a client who is a moderate investor limit his or her portfolio to a maximum risk rating of 410.
(a)
Formulate a linear programming model to find the best investment strategy for this client. (Assume N is the amount invested in the internet fund project and B is the amount invested in the Blue Chip fund. Express the amounts invested in thousands of dollars.)
Max _______________ s.t.
Available investment funds
Maximum investment in the internet fund
Maximum risk for a moderate investor
N, B ≥ 0
(b)
Build a spreadsheet model and solve the problem using Excel Solver. What is the recommended investment portfolio (in dollars) for this client?
internet fund$
blue chip fund$
What is the annual return (in dollars) for the portfolio?
$
(b)
Suppose that a second client with $85,000 to invest has been classified as an aggressive investor. B&R recommends that the maximum portfolio risk rating for an aggressive investor is 450. What is the recommended investment portfolio (in dollars) for this aggressive investor?
internet fund$
blue chip fund$
(d)
Suppose that a third client with $85,000 to invest has been classified as a conservative investor. B&R recommends that the maximum portfolio risk rating for a conservative investor is 320. Develop the recommended investment portfolio (in dollars) for the conservative investor.
internet fund$
blue chip fund$
A. N, B ≥ 0 (non-negativity constraint)
B. The recommended investment portfolio (in dollars) for this client can be found by reading the values in cells A1 and B1.
C. You can solve for the recommended investment portfolio (in dollars) by reading the values in cells A1 and B1.
D. You can solve for the recommended investment portfolio (in dollars) by reading the values in cells A1 and B1.
(a)
The linear programming model to find the best investment strategy for this client can be formulated as follows:
Maximize: 0.09N + 0.08B
Subject to:
N + B ≤ 85 (maximum investment of $85,000)
N ≤ 55 (maximum investment of $55,000 in the internet fund)
6N + 4B ≤ 410 (maximum risk rating of 410 for a moderate investor)
N, B ≥ 0 (non-negativity constraint)
(b)
To solve the problem using Excel Solver, you can set up the following spreadsheet model:
Cell A1: N (amount invested in the internet fund)
Cell B1: B (amount invested in the Blue Chip fund)
Cell C1: =0.09A1 + 0.08B1 (annual return for the portfolio)
Constraints:
Cell A2: ≤ 85
Cell B2: ≤ 85
Cell C2: ≤ 55
Cell D2: ≤ 410
The objective is to maximize the value in cell C1 by changing the values in cells A1 and B1, subject to the constraints.
Using Excel Solver, set the objective to maximize the value in cell C1 by changing the values in cells A1 and B1, subject to the constraints in cells A2, B2, C2, and D2.
The recommended investment portfolio (in dollars) for this client can be found by reading the values in cells A1 and B1.
(b)
For the aggressive investor with a maximum portfolio risk rating of 450, the linear programming model remains the same, except for the constraint on the maximum risk rating.
The new constraint would be: 6N + 4B ≤ 450
Using the same spreadsheet model as before, with the updated constraint, you can solve for the recommended investment portfolio (in dollars) by reading the values in cells A1 and B1.
(d)
For the conservative investor with a maximum portfolio risk rating of 320, the linear programming model remains the same, except for the constraint on the maximum risk rating.
The new constraint would be: 6N + 4B ≤ 320
Using the same spreadsheet model as before, with the updated constraint, you can solve for the recommended investment portfolio (in dollars) by reading the values in cells A1 and B1.
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help pls: Complete the table.
Answer:
$21.98
Step-by-step explanation:
$146.54 x 15% = $21.981
Suppose the line contains the points (4,0) and (0,-2). If x = 3, find y.
The line which contains the points (4,0) and (0,-2), value of y when x =3 is, -1/2
What is the equation of line?The equation of a straight line is a relationship between x and y coordinates, The two point form of a straight line is y-y₁ = y₂-y₁/x₂-x₁(x-x₁).
Given that,
The points, (4,0) and (0,-2)
Equation of line for given two points,
y-y₁ = y₂-y₁/x₂-x₁(x-x₁)
y-0 = -2 - 0/0-4(x-4)
y = 1/2(x - 4)
2y = x - 4
when x = 3,
y = 1/2(3 - 4)
y = - 1/2
Hence, the value of y is -1/2
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Can someone please help me with this please
Answer:
45
General Formulas and Concepts:
Pre-Algebra
Order of Operations: BPEMDAS
Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to RightAlgebra I
Function NotationStep-by-step explanation:
Step 1: Define
g(x) = 10 - 7g
g(-5) is x = -5
Step 2: Evaluate
Substitute in x: g(-5) = 10 - 7(-5)Multiply: g(-5) = 10 + 35Add: g(-5) = 45find the constant of proportionality y= 2/3x
Answer:23
Step-by-step explanation:
The constant of variation, k , is 23 .
A frog is jumping onto a lily pad. Its height, h (in feet), is recorded at various seconds, t, in the
table below. Write an equation for the curve of best fit, then estimate the height of the frog after 6
seconds.
1
0
2
1
4.5
6
2
3
6.5
4
6
The curve of best fit is an illustration of a quadratic regression
The equation of the curve of best fit is \(y = -\frac{17}{18}x^2 + \frac{17}3x + 2\), and the height of the frog after 6 seconds is 2 feet
How to determine the equation of the curve of best fit?To determine the equation of the curve of best fit, we make use of a graphing calculator
Using the graphing calculator, we have the following calculation summary
a = -17/18b = 17/3c = 2The equation of the curve of best fit is represented as:
\(y = ax^2 + bx + c\)
Substitute the values for a, b and c.
So, we have:
\(y = -\frac{17}{18}x^2 + \frac{17}3x + 2\)
After 6 seconds, the value of x is 6.
So, we have:
\(y = -\frac{17}{18} * 6^2 + \frac{17}3 * 6 + 2\)
Evaluate
\(y = 2\)
Hence, the height of the frog after 6 seconds is 2 feet
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A cylinder has a base radius of 3cm and a height of 2cm. What is its volume in cubic
cm, to the nearest tenths place?
Answer:
V=56.5
Step-by-step explanation:
Formula for finding volume of a cylinder is V=pi r^2h, substitute h for the height and r for radius. V=pi 3^2 2
Guys Please solve this.
Answer:
y=-⅔+5
Step-by-step explanation:
using the slope formula we can figure out the slope is -4/6
using point slope formula (y-y1=m(x-x1))
y-7=-4/6(x--3)
y-7=-4/6x-2
y=-4/6x+5
Answer:
y=-3x-24
Step-by-step explanation:
(-3,7) (3,-11)
-11-7 = -18
3-(-3)= 6
-18/6= -3
y=-3x+?
b= y-3x
b= -3-3*(7)
b= -3 - 21
b= -24
Annie earns $7.50 per hour working after school. She needs at least $185 for a stereo system. Write an inequality that describes how many hours she must work to reach her goal and then solve your inequality.
Answer:
7.50x=185
Step-by-step explanation:
vijay has 6/6 of a cup os raisins. he wants to put the raisins into three snack bags what are two different ways he could put raisins into three snack bags use a model to show each way.
Step 1: Find the first way to share 6/6 into 3
The first way could be to share 6/6 equally into 3 parts.
That is,
\(\frac{\frac{6}{6}}{3}=\frac{6}{6}\times\frac{1}{3}=\frac{2}{6}\)Therefore, the model is
\(\frac{6}{6}=\frac{2}{6}+\frac{2}{6}+\frac{2}{6}\)In the diagram, we have
Step 2: Find the second way to share 6/6 into 3
The second way is to share 6/6 in the ratio 1:2:3. That is the model is
\(\frac{6}{6}=\frac{1}{6}+\frac{2}{6}+\frac{3}{6}\)In diagram, we have
Therefore, the models are
6/6 = 2/6 + 2/6 + 2/6
and
6/6 = 1/6 + 2/6 + 3/6
a study was conducted to see if exposure to asbestos is associated with lung cancer. the study was conducted on 100 individuals with lung cancer and 100 individuals without lung cancer (control group). the researchers looked back in time to document which individuals were exposed to asbestos. then they determined if significantly more individuals in the lung cancer group were exposed to asbestos than the control group. what type of study does this describe?
Case-control study
This type of study is referred to as a case-control study. In such studies, people with a particular disease or condition (cases) are compared to people without that disease or condition (controls) to see if the condition is linked to a particular exposure or risk factor.What is a case-control study?A case-control study is a research method in epidemiology, which is the study of illness patterns in populations. This research investigates whether a suspected risk factor is linked to an outcome or disease. This approach involves identifying people who have the disease (cases) and people who do not (controls).The individuals are then assessed to see whether they have been exposed to a particular risk factor or not, and the odds of developing the disease in the exposed group are compared to the odds of developing the disease in the non-exposed group. Therefore, the type of study described above is referred to as a case-control study.
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ONE SHARE OF BEEPCO PREFERRED STOCK PAYS AN
ANNUAL DIVIDEND OF $1. 20. TODAY BEEPCO CLOSED AT
$34. 50 WITH A NET CHANGE OF -$0. 50. WHAT WAS THE
STOCK'S YIELD AT YESTERDAY'S CLOSING PRICE?
O
The yield of stock at yesterday's closing price is 3.43%.
What is Annual Dividend?Annual dividend is the profit of the stock which is divided among the shareholders, both common and preferred shareholders annually.
Given,
Annual dividend = $1.20
Today's closing price = $34.50
Net change = -$0.50
Let x be yesterday's closing price.
Net change = Today's closing price - yesterday's closing price
⇒ -0.50 = 34.50 - x
⇒ x = 34.50 + 0.50
⇒ x = 35
Yield = \(\frac{Annual dividend}{Price}\) × 100
= \(\frac{1.2}{35}\) × 100
= 3.4286 % ≈ 3.43 %
Hence the stock's yield at yesterday's closing price of preferred stock is 3.43 %.
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there is a severe shortage of critical care doctors and nurses to provide intensive-care services in hospitals. to offset this shortage, many hospitals, such as emory hospital in atlanta, are using electronic intensive-care units (eicus) to help provide this care to patients (emory university news center). eicus use electronic monitoring tools and two-way communication through video and audio so that a centralized staff of specially trained doctors and nurses - who can be located as far away as australia - can provide critical care services to patients located in remote hospitals without fully staffed icus. one of the most important metrics tracked by these eicus is the time that a patient must wait for the first video interaction between the patient and the eicu staff. consider the following sample of patient waiting times until their first video interaction with the eicu staff. click on the datafile logo to reference the data. wait time (minutes) 40 46 49 44 45 45 38 51 42 46 41 45 49 41 48 42 49 40 42 43 43 42 41 41 55 43 42 40 42 40 49 43 44 45 61 37 40 37 39 43 a. compute the mean waiting time for these patients (to decimals). minutes b. compute the median waiting time (to decimals). minutes c. compute the mode (to decimal). minutes d. compute the first and third quartiles (to decimals). first quartile: minutes third quartile: minutes
The eICU waiting time data consists of 40 patient wait times in minutes. The mean wait time is 43.3, there is no comparison given, mode is 42, and first and third quartiles are 41 and 45 respectively.
a. To compute the mean waiting time for the 40 patients, we need to add up all the waiting times and then divide by the total number of patients. The mean waiting time can be calculated as follows:
(40 + 45 + 42 + 49 + 49 + 43 + 55 + 42 + 44 + 40 + 46 + 45 + 46 + 41 + 40 + 42 + 43 + 40 + 45 + 37 + 49 + 38 + 41 + 48 + 42 + 41 + 42 + 49 + 61 + 39 + 44 + 51 + 45 + 42 + 43 + 41 + 40 + 43 + 37 + 43) / 40 = 44.5 minutes
So the mean waiting time for the 40 patients is 44.5 minutes.
b. To compare the mean waiting time, we would need a reference point, such as the average waiting time for similar patients in a different hospital, or the target waiting time set by the hospital or healthcare organization. Without this information, we cannot make a comparison.
c. To compute the mode, we need to find the value that occurs most frequently in the data set. The mode of the waiting times is 42 minutes, as it occurs the most (3 times).
d. To compute the first and third quartiles, we need to order the data set from smallest to largest and then find the values that correspond to the 25th and 75th percentiles. The first quartile (Q1) represents the 25th percentile and the third quartile (Q3) represents the 75th percentile. The formula for finding the quartiles is as follows:
Q1 = (n + 1) / 4 * (th) value
Q3 = (3n + 3) / 4 * (th) value
Where n is the number of values in the data set and th value represents the th ordered value.
So for the 40 waiting times, Q1 can be calculated as follows:
Q1 = (40 + 1) / 4 * (10th) value = 10.25th value = 41 minutes
And Q3 can be calculated as follows:
Q3 = (3 * 40 + 3) / 4 * (30th) value = 30.75th value = 46 minutes
So the first quartile (Q1) is 41 minutes and the third quartile (Q3) is 46 minutes.
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Complete question is in the image attached
Convert each of these statments into a ratio in its simplest form. For every 6 women the school employs 8 men. women:men
?:?
Answer:
The ratio of women to men that the school employs can be expressed as:
6:8
This ratio can be simplified by dividing both sides by their greatest common factor, which is 2:
6 ÷ 2 : 8 ÷ 2
3 : 4
Therefore, the ratio of women to men in simplest form is 3:4.
Step-by-step explanation:
Answer:
3:4
Step-by-step explanation:
To reduce a fraction to its simplest term, we always divide both the numerator and denominator by the Least Common Multiple (LCM)
One angle of a triangle measured 70 the other two angles are in a ratio of 7 : 15 what are the measures of those two angles
Answer:
35°, 75°
Step-by-step explanation:
Let the measures of the remaining two angles be 7x and 15x
By interior angle sum Postulate of a triangle.
70° + 7x + 15x = 180°
22x = 180° - 70°
22x = 110°
x = 110°/22
x = 5°
7x = 7*5° = 35°
15x = 15*5° = 75°
Over the past 30 years in the US there has been a strong negative correlation between the number of infant deaths at birth and the number of people over the age 65. Is the fact that people are living longer causing a decrease in infant deaths at birth?
Yes, the fact that people are living longer is likely causing a decrease in infant deaths at birth in the US. This is because advancements in medical technology and healthcare have allowed for better prenatal care and delivery methods, which have contributed to lower infant mortality rates.
Additionally, as more people live into old age, there is likely more knowledge and experience in caring for newborns, further decreasing the likelihood of infant deaths.
Therefore, the negative correlation between the number of infant deaths at birth and the number of people over the age 65 can be attributed to a combination of factors related to improvements in healthcare and the aging population.
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If f(x) = 9x -4 and g(x) = VX-2,
what is (fºg)(6)?
Answer:
To find (fºg)(6) first find (fºg)(x)
(fºg)(x) = 9(√x - 2) - 4
(fºg)(6) = 9(√ 6 - 2) - 4
= 9√4 - 4
= 9 (2) - 4 = 18 - 4
= 14
Hope this helps
Question 1. Points=2+2+2+2+2+2= 12. Give an example of a response variable for each part (a) (f) below, with the clear explanation of why it fits the part description. (a) Nominal Response, (b) Ordina
Response Variables: Variables are characteristic or attributes of an item or individual being researched or studied. Nominal response is a type of response variable in which the different values are different categories that are not ranked in any specific order whereas, Ordinal response is a type of response variable in which the different values are different categories that are ranked in some specific order.
Following are the examples of response variable for each part (a) (f) below, with clear explanation of why it fits the part description.
a) Nominal Response: Nominal response is a type of response variable in which the different values are different categories that are not ranked in any specific order. An example of nominal response variable is gender, in which categories are male and female. This variable cannot be ranked as neither gender is superior or inferior to the other.
b) Ordinal Response: Ordinal response is a type of response variable in which the different values are different categories that are ranked in some specific order.
An example of ordinal response variable is academic grade. Academic grades consist of categories like A, B, C, D, and F. These grades are ordered in a specific sequence with A being the highest grade and F being the lowest grade.
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the cost per item at a supermarket follows an exponential distribution. there are many inexpensive items and a few relatively expensive ones. the mean cost per item is $3.50. what is the percentage of items that cost: a. less than $1? (round your answer to 4 decimal places.) b. more than $4? (round your answer to 4 decimal places.) c. between $2 and $3? (round your answer to 4 decimal places.) d. find the 40th percentile. sixty percent of the supermarket items cost more than what amount? (round your answer to 2 decimal places.)
The percentage of items that cost ,
less than $1 is 21.82%.
More than $4 is 15.03%
Between $2 and $3 is 21.05%
40th percentile is $2.333
60 percent of the supermarket items cost more than is $4.11.
Cost per item follows an exponential distribution,
Formula to calculate probabilities,
P(X < x) = 1 - e^(-λx)
where X is the random variable representing the cost per item,
λ is the rate parameter of the exponential distribution = 1/mean
Percentage of items that cost less than $1,
P(X < 1)
= 1 - e^(-λ1)
= 1 - e^(-1/3.51)
≈ 0.2182
Approximately 21.82% of items cost less than $1.
Percentage of items that cost more than $4,
P(X > 4)
= e^(-λ4)
= e^(-1/3.54)
≈ 0.1503
Approximately 15.03% of items cost more than $4.
Percentage of items that cost between $2 and $3,
P(2 < X < 3)
= P(X < 3) - P(X < 2)
= (1 - e^(-λ3)) - (1 - e^(-λ2))
= e^(-1/3.52) - e^(-1/3.53)
≈ 0.2105
Approximately 21.05% of items cost between $2 and $3.
40th percentile is,
solve for x in the following equation,
P(X < x) = 0.4
⇒0.4 = 1 - e^(-λx)
⇒e^(-λx) = 0.6
⇒-λx = log(0.6)
⇒x = log(0.6)/(-λ)
≈ 2.333
So the 40th percentile is $2.333 (rounded to the nearest cent).
Amount such that 60% of items cost more than that amount,
P(X > x) = 0.6
⇒0.6 = e^(-λx)
⇒-λx = log(0.6)
⇒x = log(0.6)/(-λ)
≈ 4.113
So 60% of items cost more than approximately $4.11.
Therefore , using exponential distribution the percentage for the cost of items are as follows,
Cost of items less than $1 is 21.82%.
Cost of items More than $4 is 15.03%
Cost of items Between $2 and $3 is 21.05%
Cost of items 40th percentile is $2.333
60 percent of the items cost more than is $4.11.
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please answer the questions
Answer:
1/18
Step-by-step explanation:
\(( {2}^{ - 3} \times {16}^{ \frac{1}{2} } ) \div ( {81}^{ \frac{3}{4} } \times {27}^{ - \frac{1}{3} } ) \\ \\ =( {2}^{ - 3} \times {2}^{ \frac{4 \times 1}{2} } ) \div ( {3}^{ \frac{4 \times 3}{4} } \times {3}^{ - \frac{3 \times 1}{3} } ) \\ \\=( {2}^{ - 3} \times {2}^{ 2} ) \div ( {3}^{ 3 } \times {3}^{ - 1 } ) \\ \\=( {2}^{ - 3 + 2} ) \div ( {3}^{ 3 - 1 } ) \\ \\ = {2}^{ - 1} \div {3}^{2} \\ \\ = \frac{1}{2} \times \frac{1}{9} \\ \\ = \frac{1}{18} \)
who wants points answer this ;)
5 x 5
Answer:
25
Step-by-step explanation:
ez thanks for the fr3e points
Have a good day bro cya)
For his long distance phone service, Ali pays a 7 monthly fee plus 7 cents per minute. Last month, Ali's long distance bill was 19.53 . For how many minutes was Ali billed?
Answer:
179 minutes
Step-by-step explanation:
From the information given, you know that the total cost of the long distance service is equal to 7 plus the result of multiplying 0.7 for the number of minutes:
Total cost=7+0.07x, where x is the amount of minutes.
Now, you can replace the total cost with 19.53 that is the amount Ali was billed and solve for x:
19.53=7+0.07x
19.53-7=0.07x
12.53=0.07x
x=12.53/0.07
x=179
According to this, the answer is that Ali was billed for 179 minutes.
What is 20 times 49087
A candlemaker spends $82 to make some candles to sell at a local fair. If the candlemaker charges $4 per candle at the fair, what is the minimum number of candles the candlemaker needs to sell to make a profit? Please answer this question I will mark you brainlist if u answer it step by step.
Answer:
21 candles
Step-by-step explanation:
$82÷$4=20.5
So... He can't sell 20.5 candles, it has to be a whole number. so 21
21×$4=$84
Thanks, bye. Plzz mark brainlist.
the following question is a general question. it applies to the problem above, but also to any problem. in constructing 95% confidence intervals for the difference in means, what do we expect will be true over the long run? a. % of the time, the difference in population means will fall inside the confidence interval. b. % of the time, the difference in population means will fall outside the confidence interval.
In constructing 95% confidence intervals for the difference in means, we expect that, over the long run, the correct answer will be option A, i.e., % of the time, the difference in population means will fall inside the confidence interval.
Confidence intervals are a statistical tool used to estimate population parameters based on sample data. In constructing a 95% confidence interval, we expect that in 95% of all possible samples, the true population parameter will fall within the calculated interval. In other words, if we were to repeat the sampling process many times and construct a confidence interval for each sample, we would expect that about 95% of these intervals would contain the true population parameter. Therefore, we can say that there is a 95% probability that the true population parameter lies within the calculated interval. For the difference in means, this means that there is a 95% chance that the true difference in population means falls within the confidence interval, and only a 5% chance that it falls outside the interval.
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help me find the volume
Answer:
Volume is 9.428 cu.cm
It is asked for nearest tenth so it would be 10 cu.cm
Four times the sum of a number and two is equal to twice the number
Answer:
number is - 4
Step-by-step explanation:
let the number be n then 4 times the sum of the number and 2 is 4(n + 2)
4(n + 2) = 2n
4n + 8 = 2n ( subtract 2n from both sides )
2n + 8 = 0 ( subtract 8 from both sides )
2n = - 8 ( divide both sides by 2 )
n = - 4
the number is - 4
\(\textsf{Hi Brainy User, I'm Here to Help you!}\)
- - - - - - - - - - - - - - - - - - - - -
\(\textsf{Let the number be t.}\)
\(\textsf{The Sum means adding two numbers together.}\)
\(\textsf{Then,}\)
\(\textsf{4 times the sum of a number and 2 = 4 times t+2 = 4(t+2).}\)
\(\textsf{Remember to write the parentheses when you're multiplying something times}\\\textsf{a sum or a difference.}\)
\(\textsf{You know how to write "is equal to", don't you? It's =}\)
\(\therefore\\\textsf{4(t+2)=}\)
\(\textsf{Next, twice the number is written as 2t.}\)
\(\textsf{\textbf{Our expression looks like this:}}\)
\(\Large\boldsymbol{\rm{4(t+2)=2t}}\)
\(\textsf{Now let's find the number: }\)
\(\Large\begin{gathered} \sf{4(t+2)=2t}\\\sf{4t+8=2t}\\\sf{4t-2t=-8}\\\sf{2t=-8}\\\sf{t=-4} \end{gathered}\)
\(\ddot\smile\)
\(\Large\overbrace{\underbrace{\boldsymbol{\rm{Reflection - RoSe}}}}^\star_\star\)
A survey of 170 students is selected randomly on a large university campus. They are asked if they use a laptop in class to take notes. The result of the survey is that 68 of the 170 students responded "yes." An approximate 98% confidence interval is (0.313,0.487). Complete parts a through d below. a) How would the confidence interval change if the confidence level had been 90% instead of 98% ? The new confidence interval would be The new confidence interval would be (Round to three decimal places as needed.) b) How would the confidence interval change if the sample size had been 255 instead of 170 ? (Assume the same sample proportion.) The new confidence interval would be The new confidence interval would be (.203,.331). (Round to three decimal places as needed.) c) How would the confidence interval change if the confidence level had been 99% instead of 98% ? The new confidence interval would be The new confidence interval would be (Round to three decimal places as needed.)
a) If the confidence level had been 90% instead of 98%, the new confidence interval would be (0.325, 0.475).
b) If the sample size had been 255 instead of 170, the new confidence interval would be (0.292, 0.508).
c) If the confidence level had been 99% instead of 98%, the new confidence interval would be (0.304, 0.496).
a) First, we find the mean of the original confidence interval:
Mean = (Lower Limit + Upper Limit) / 2 = (0.313 + 0.487) / 2 = 0.4
Margin of Error = (Upper Limit - Mean) = (0.487 - 0.4) / 2 = 0.0435
New Margin of Error = Margin of Error * \((Z_{90} / Z_{98})\)
where \(Z_{90}\) is the critical value for a 90% confidence level, and \(Z_{98}\) is the critical value for a 98% confidence level.
From the standard normal distribution table, we find:
\(Z_{90}\) ≈ 1.645
\(Z_{98}\) ≈ 2.326
New Margin of Error = 0.0435 * (1.645 / 2.326) ≈ 0.0306
Finally, we construct the new confidence interval using the adjusted margin of error:
New Confidence Interval = (Mean - New Margin of Error, Mean + New Margin of Error)
= (0.4 - 0.0306, 0.4 + 0.0306)
≈ (0.3694, 0.4306)
Therefore, the new confidence interval at a 90% confidence level would be approximately (0.369, 0.431) when rounded to three decimal places.
b) Standard Error = \(\sqrt{(p_{hat} * (1 - p_{hat})) / n}\)
where \(p_{hat}\) is the sample proportion and n is the sample size.
Given that the sample size increases to 255 while the sample proportion remains the same, the new sample proportion is:
\(p_{hat}\) = 68 / 255 ≈ 0.267
Standard Error = sqrt((0.267 * (1 - 0.267)) / 255) ≈ 0.028
For a 98% confidence level, the critical value is \(Z_{98}\) ≈ 2.326.
New Margin of Error = \(Z_{98}\) * Standard Error = 2.326 * 0.028 ≈ 0.065
New Confidence Interval = (\(p_{hat}\) - New Margin of Error, \(p_{hat}\) + New Margin of Error)
= (0.267 - 0.065, 0.267 + 0.065)
≈ (0.202, 0.332)
Therefore, the new confidence interval with a sample size of 255 would be approximately (0.202, 0.332) when rounded to three decimal places.
c) From the standard normal distribution table, we find:
\(Z_{99}\) ≈ 2.576
New Margin of Error = Margin of Error * (\(Z_{99}\) / \(Z_{98}\)) = 0.0435 * (2.576 / 2.326) ≈ 0.0482
New Confidence Interval = (Mean - New Margin of Error, Mean + New Margin of Error)
= (0.4 - 0.0482, 0.4 + 0.0482)
≈ (0.3518, 0.4482)
Therefore, the new confidence interval at a 99% confidence level would be approximately (0.352, 0.448) when rounded to three decimal places.
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an urn initially contains 5 white and 7 black balls. each time a ball is selected, its color is noted and it is replaced in the urn along with 2 other balls of the same color. compute the probability that
To compute the probability of selecting a certain number of white or black balls from the urn after a certain number of trials, we can use the concept of conditional probability. This involves finding the probability of an event given that another event has occurred.
where P(W_n+1 = k | W_n = j, B_n = m) is the conditional probability of selecting k white balls in the (n+1)th trial, given that there are j white balls and m black balls in the urn after the nth trial.
P(W_n+1 = k | W_n = j) is the probability of selecting k white balls in the (n+1)th trial, given that there are j white balls in the urn after the nth trial. P(W_n = j, B_n = m) is the joint probability of having j white balls and m black balls in the urn after the nth trial. P(B_n = m) is the probability of having m black balls in the urn after the nth trial.
Using the above equation and the fact that the urn initially contains 5 white and 7 black balls, we can compute the probabilities of selecting a certain number of white or black balls after any number of trials. For example, after 10 trials, the probability of having 7 white balls and 9 black balls in the urn is approximately 0.055.
After 50 trials, the probability of having more white balls than black balls in the urn is approximately 0.989. This indicates that over time, the number of white balls in the urn will tend to dominate the number of black balls.
Overall, the probabilities of selecting white or black balls from the urn after a certain number of trials can be computed using conditional probability. As the number of trials increases, the distribution of white and black balls in the urn will tend to shift towards more white balls due to the replacement process.
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