Week 5 Test
Part 1 of 4 - Z-interval for Unknown Questions 7.0/ 7.0 Points
Question 1 of 20
1.0/ 1.0 Points
The population standard deviation for the height of college basketball players is 3.4 inches. If
we want to estimate 99% confidence interval for the population mean height of these players
with a 0.43 margin of error, how many randomly selected players must be surveyed? (Round up
your answer to nearest whole number, do not include any decimals) Answer: 415
Answer Key: 415
Feedback:
Z-Critical Value =NORM.S.INV(.995) =2.575
n=
Question 2 of 20
1.0/ 1.0 Points
Suppose a marketing company wants to determine the current proportion of customers who click
on ads on their smartphones. It was estimated that the current proportion of customers who click
on ads on their smartphones is 0.65. How many customers should the company survey in order
to be 94% confident that the margin of error is 0.22 for the confidence interval of true
proportion of customers who click on ads on their smartphones? Answer: (Round up your
answer to nearest whole number,do not include any decimals) 17
Answer Key: 17
Feedback:
Z-Critical Value = NORM.S.INV(..97) = 1.880794
n=
Question 3 of 20
1.0/ 1.0 Points
The population standard deviation for the height of college basketball players is 3.1 inches. If
we want to estimate 99% confidence interval for the population mean height of these players
with a 0.58 margin of error, how many randomly selected players must be surveyed? (Round up
, your answer to nearest whole number, do not include any decimals) Answer: 190
Answer Key: 190
Feedback:
Z-Critical Value =NORMS.INV(.995) = 2.575
n=
Question 4 of 20
1.0/ 1.0 Points
There is no prior information about the proportion of Americans who support gun control in
2019. If we want to estimate 93% confidence interval for the true proportion of Americans who
support gun control in 2019 with a 0.18 margin of error, how many randomly selected
Americans must be surveyed? Answer: (Round up your answer to nearest whole number, do not
include any decimals) 26
Answer Key: 26
Feedback:
Z-Critical Value = NORM.S.INV(.965) = 1.811911
n=
Question 5 of 20
1.0/ 1.0 Points
There is no prior information about the proportion of Americans who support free trade in 2019.
If we want to estimate a 98% confidence interval for the true proportion of Americans who
support free trade in 2019 with a 0.21 margin of error, how many randomly selected Americans
must be surveyed? Answer: (Round up your answer to nearest whole number, do not include
any decimals) 31
Answer Key: 31
Feedback:
Z-Critical Value = NORM.S.INV(.99) = 2.326348
n=
Part 1 of 4 - Z-interval for Unknown Questions 7.0/ 7.0 Points
Question 1 of 20
1.0/ 1.0 Points
The population standard deviation for the height of college basketball players is 3.4 inches. If
we want to estimate 99% confidence interval for the population mean height of these players
with a 0.43 margin of error, how many randomly selected players must be surveyed? (Round up
your answer to nearest whole number, do not include any decimals) Answer: 415
Answer Key: 415
Feedback:
Z-Critical Value =NORM.S.INV(.995) =2.575
n=
Question 2 of 20
1.0/ 1.0 Points
Suppose a marketing company wants to determine the current proportion of customers who click
on ads on their smartphones. It was estimated that the current proportion of customers who click
on ads on their smartphones is 0.65. How many customers should the company survey in order
to be 94% confident that the margin of error is 0.22 for the confidence interval of true
proportion of customers who click on ads on their smartphones? Answer: (Round up your
answer to nearest whole number,do not include any decimals) 17
Answer Key: 17
Feedback:
Z-Critical Value = NORM.S.INV(..97) = 1.880794
n=
Question 3 of 20
1.0/ 1.0 Points
The population standard deviation for the height of college basketball players is 3.1 inches. If
we want to estimate 99% confidence interval for the population mean height of these players
with a 0.58 margin of error, how many randomly selected players must be surveyed? (Round up
, your answer to nearest whole number, do not include any decimals) Answer: 190
Answer Key: 190
Feedback:
Z-Critical Value =NORMS.INV(.995) = 2.575
n=
Question 4 of 20
1.0/ 1.0 Points
There is no prior information about the proportion of Americans who support gun control in
2019. If we want to estimate 93% confidence interval for the true proportion of Americans who
support gun control in 2019 with a 0.18 margin of error, how many randomly selected
Americans must be surveyed? Answer: (Round up your answer to nearest whole number, do not
include any decimals) 26
Answer Key: 26
Feedback:
Z-Critical Value = NORM.S.INV(.965) = 1.811911
n=
Question 5 of 20
1.0/ 1.0 Points
There is no prior information about the proportion of Americans who support free trade in 2019.
If we want to estimate a 98% confidence interval for the true proportion of Americans who
support free trade in 2019 with a 0.21 margin of error, how many randomly selected Americans
must be surveyed? Answer: (Round up your answer to nearest whole number, do not include
any decimals) 31
Answer Key: 31
Feedback:
Z-Critical Value = NORM.S.INV(.99) = 2.326348
n=
