ESTIMATION CHECKPOINT
P 207
Step 1 of 1
Question 1 of 7Points: 10 out of 10
We say that a point estimator is unbiased if (choose one):
its sampling distribution is centered exactly at the parameter it estimates.
the standard deviation of its sampling distribution decreases as the sample
size increases.
its sampling distribution is normal.
its value is always equal to the parameter it estimates.
Good job! This is the definition of an unbiased estimator (see the second page
about Point Estimation).
The next four questions refer to the following information:
A study was conducted in order to estimate μ, the mean number of weekly hours that U.S. adults use
computers at home. Suppose a random sample of 81 U.S. adults gives a mean weekly computer usage
time of 8.5 hours and that from prior studies, the population standard deviation is assumed to be σ = 3.6
hours.
Question 2 of 7Points: 10 out of 10
Based on this information, what would be the point estimate for μ?
81
8.5
3.6
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, None of the above.
Good job! The point estimate for the population mean μ is the sample mean, x
ˉ . In this case, to estimate the mean number of weekly hours of home
computer use among the population of U.S. adults, we used the sample mean
obtained from the sample, therefore x ˉ = 8.5.
Question 3 of 7Points: 10 out of 10
We are 95% confident that the mean number of weekly hours that U.S. adults
use computers at home is:
between 8.1 and 8.9.
between 7.8 and 9.2.
between 7.7 and 9.3.
between 7.5 and 9.5.
between 7.3 and 9.7.
Good job! The 95% confidence interval for the mean, μ, is x ˉ ± 2 ⋅ σ n = 8.5 ±
2 ⋅ 3.6 81 = 8.5 ± . 8 = ( 7.7 , 9.3 ) . .
Question 4 of 7Points: 10 out of 10
Which of the following will provide a more informative (i.e., narrower)
confidence interval than the one in problem 3?
Using a sample of size 400 (instead of 81).
Using a sample of size 36 (instead of 81).
Using a different sample of size 81.
This study source was downloaded by 100000824189183 from CourseHero.com on 03-09-2022 09:51:40 GMT -06:00
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P 207
Step 1 of 1
Question 1 of 7Points: 10 out of 10
We say that a point estimator is unbiased if (choose one):
its sampling distribution is centered exactly at the parameter it estimates.
the standard deviation of its sampling distribution decreases as the sample
size increases.
its sampling distribution is normal.
its value is always equal to the parameter it estimates.
Good job! This is the definition of an unbiased estimator (see the second page
about Point Estimation).
The next four questions refer to the following information:
A study was conducted in order to estimate μ, the mean number of weekly hours that U.S. adults use
computers at home. Suppose a random sample of 81 U.S. adults gives a mean weekly computer usage
time of 8.5 hours and that from prior studies, the population standard deviation is assumed to be σ = 3.6
hours.
Question 2 of 7Points: 10 out of 10
Based on this information, what would be the point estimate for μ?
81
8.5
3.6
This study source was downloaded by 100000824189183 from CourseHero.com on 03-09-2022 09:51:40 GMT -06:00
https://www.coursehero.com/file/27465427/Quiz-18-ESTIMATION-CHECKPOINTdocx/
, None of the above.
Good job! The point estimate for the population mean μ is the sample mean, x
ˉ . In this case, to estimate the mean number of weekly hours of home
computer use among the population of U.S. adults, we used the sample mean
obtained from the sample, therefore x ˉ = 8.5.
Question 3 of 7Points: 10 out of 10
We are 95% confident that the mean number of weekly hours that U.S. adults
use computers at home is:
between 8.1 and 8.9.
between 7.8 and 9.2.
between 7.7 and 9.3.
between 7.5 and 9.5.
between 7.3 and 9.7.
Good job! The 95% confidence interval for the mean, μ, is x ˉ ± 2 ⋅ σ n = 8.5 ±
2 ⋅ 3.6 81 = 8.5 ± . 8 = ( 7.7 , 9.3 ) . .
Question 4 of 7Points: 10 out of 10
Which of the following will provide a more informative (i.e., narrower)
confidence interval than the one in problem 3?
Using a sample of size 400 (instead of 81).
Using a sample of size 36 (instead of 81).
Using a different sample of size 81.
This study source was downloaded by 100000824189183 from CourseHero.com on 03-09-2022 09:51:40 GMT -06:00
https://www.coursehero.com/file/27465427/Quiz-18-ESTIMATION-CHECKPOINTdocx/
