BESC 3010 - TEST 2 QUESTIONS
WITH ALL CORRECT ANSWERS
Imagine that samples - Sample A with n = 20 and Sample B with n = 200 - are drawn
from the same population and confidence intervals are computed for the same
variables, which sample will likely have the more precise confidence interval? - Answer-
Sample B
How is a confidence interval affected when the sample standard deviation decreases? -
Answer-It becomes narrower
When the range of confidence for a confidence interval becomes lower - from 90% to
80%, for example - then the confidence interval will... - Answer-Become narrower
What is the point estimate for the population mean if the population standard deviation
is 24, the sample size is 36, and the sample mean is 110? - Answer-110
As the mean for a distribution increases, then the width of the corresponding confidence
interval will... - Answer-Stay the same
Imagine a sample with n = 49 and a mean of 60 that comes from a population with a
standard deviation of 7. Based on these data, what would be the 99.9% confidence
interval for the population mean? (Use z-score of +3.29 for the 99.9% confidence level.)
- Answer-(56.71, 63.29)
The sample mean is ________ and a confidence interval for the mean is _______. -
Answer-a descriptive statistic; an inferential statistic
Which is more precise (in the statistical sense): a point estimate or a confidence
interval? - Answer-A point estimate
If a researcher wants to test whether an experimental group is different from the general
population, the she would test... - Answer-the null hypothesis of no difference between
the group and the population.
In a two-tailed or non-directional test, if the critical value has a greater absolute value
than the observed (or test) value does, the the null hypothesis... - Answer-is not rejected
(i.e., retained).
When calculating an effect size for the z-test... - Answer-the sample size is irrelevant.
, What does it mean when the result of a z-test is called "statistically significant"? -
Answer-The alpha value was greater than p-value
A Type I error occurs when... - Answer-The sample data lead us to reject a null
hypothesis that is true
A Type II error occurs when... - Answer-the sample data lead us to retain (i.e., fail to
reject) a null hypothesis that is false.
When choosing a level of alpha for a hypothesis test, unless you have a compelling
reason to do otherwise, you should use... - Answer-.05
If a researcher is using an alpha of .05 for a z-test and gets an observed (or test) p-
value of .23, then the researcher should... - Answer-retain (i.e., fail to reject) the null
hypothesis
If a researcher is using an critical value of ±1.96 for a z-test and gets an observed (or
test) z of -1.73, then the researcher should... - Answer-retain (i.e., fail to reject) the null
hypothesis.
Imagine that a researcher is interested in whether residents in his local area have
higher levels of well-being than the national average. What would be an appropriate
alternate hypothesis for a one-tailed or directional z-test for this test? - Answer-local
residents average > national average
Imagine two studies that are identical in every respect except the size of their samples.
Sample A has an effect size of d = .20 and a p-value of .03. Sample B has an effect size
of d = .20 and a p-value of .005. Which sample likely had the smaller sample size? -
Answer-Sample A
Imagine two studies that are identical in every respect except their effect sizes. Sample
A has a sample size of n = 80 and a p-value of .01. Sample B has a sample size of n =
80 and a p-value of .10. Which sample likely had the larger effect size? - Answer-
Sample A
When the mean of the population that a sample comes from does not differ from the
general population but the sample mean is nonetheless significantly different from the
general population, then... - Answer-a Type I error has occurred
If a researcher is comparing a sample mean to a population mean and gets Cohen's d =
-2.0, this means that... - Answer-The sample mean is two standard deviations below the
population mean
If a researcher is using alpha = .05 and gets a p-value for the z-test of p = .02, then... -
Answer-the results are unlikely to occur by chance if the null hypothesis is true.
WITH ALL CORRECT ANSWERS
Imagine that samples - Sample A with n = 20 and Sample B with n = 200 - are drawn
from the same population and confidence intervals are computed for the same
variables, which sample will likely have the more precise confidence interval? - Answer-
Sample B
How is a confidence interval affected when the sample standard deviation decreases? -
Answer-It becomes narrower
When the range of confidence for a confidence interval becomes lower - from 90% to
80%, for example - then the confidence interval will... - Answer-Become narrower
What is the point estimate for the population mean if the population standard deviation
is 24, the sample size is 36, and the sample mean is 110? - Answer-110
As the mean for a distribution increases, then the width of the corresponding confidence
interval will... - Answer-Stay the same
Imagine a sample with n = 49 and a mean of 60 that comes from a population with a
standard deviation of 7. Based on these data, what would be the 99.9% confidence
interval for the population mean? (Use z-score of +3.29 for the 99.9% confidence level.)
- Answer-(56.71, 63.29)
The sample mean is ________ and a confidence interval for the mean is _______. -
Answer-a descriptive statistic; an inferential statistic
Which is more precise (in the statistical sense): a point estimate or a confidence
interval? - Answer-A point estimate
If a researcher wants to test whether an experimental group is different from the general
population, the she would test... - Answer-the null hypothesis of no difference between
the group and the population.
In a two-tailed or non-directional test, if the critical value has a greater absolute value
than the observed (or test) value does, the the null hypothesis... - Answer-is not rejected
(i.e., retained).
When calculating an effect size for the z-test... - Answer-the sample size is irrelevant.
, What does it mean when the result of a z-test is called "statistically significant"? -
Answer-The alpha value was greater than p-value
A Type I error occurs when... - Answer-The sample data lead us to reject a null
hypothesis that is true
A Type II error occurs when... - Answer-the sample data lead us to retain (i.e., fail to
reject) a null hypothesis that is false.
When choosing a level of alpha for a hypothesis test, unless you have a compelling
reason to do otherwise, you should use... - Answer-.05
If a researcher is using an alpha of .05 for a z-test and gets an observed (or test) p-
value of .23, then the researcher should... - Answer-retain (i.e., fail to reject) the null
hypothesis
If a researcher is using an critical value of ±1.96 for a z-test and gets an observed (or
test) z of -1.73, then the researcher should... - Answer-retain (i.e., fail to reject) the null
hypothesis.
Imagine that a researcher is interested in whether residents in his local area have
higher levels of well-being than the national average. What would be an appropriate
alternate hypothesis for a one-tailed or directional z-test for this test? - Answer-local
residents average > national average
Imagine two studies that are identical in every respect except the size of their samples.
Sample A has an effect size of d = .20 and a p-value of .03. Sample B has an effect size
of d = .20 and a p-value of .005. Which sample likely had the smaller sample size? -
Answer-Sample A
Imagine two studies that are identical in every respect except their effect sizes. Sample
A has a sample size of n = 80 and a p-value of .01. Sample B has a sample size of n =
80 and a p-value of .10. Which sample likely had the larger effect size? - Answer-
Sample A
When the mean of the population that a sample comes from does not differ from the
general population but the sample mean is nonetheless significantly different from the
general population, then... - Answer-a Type I error has occurred
If a researcher is comparing a sample mean to a population mean and gets Cohen's d =
-2.0, this means that... - Answer-The sample mean is two standard deviations below the
population mean
If a researcher is using alpha = .05 and gets a p-value for the z-test of p = .02, then... -
Answer-the results are unlikely to occur by chance if the null hypothesis is true.
