Psych 311 Exam A+ Pass
Which of the following is a major difference between a hypothesis test with the t statistic
formula and the test with a z-score? - Answer- You must calculate the sample variance
(or standard deviation) for the t statistic but not for the z-score. You use the unit normal
table to find critical values for the z-score test but not for the t test. You must know the
population variance (or standard deviation) for the z-score but not for the t statistic.
On average, what value is expected for the t statistic when the null hypothesis is true? -
Answer- 0
What is measured by the estimated standard error, sM? - Answer- How much difference
is reasonable to expect between a sample mean and the population mean
A sample of n = 25 individuals is selected from a population with µ= 80, and a treatment
is administered to the sample. Which set of sample characteristics is most likely to lead
to a decision that there is a significant treatment effect? - Answer- M = 90 and small
sample variance
What is the sample variance and the estimated standard error for a sample of n = 4
scores with SS = 300 - Answer- s2 = 100 and sM = 5
With α= .01, what is the critical t value for a one-tailed test with n = 30 - Answer- t =
2.462
A sample has a mean of M = 39.5 and a standard deviation of s = 4.3. In a two-tailed
hypothesis test with α= .05, this sample produces a t statistic of t = 2.14. Based on this
information, the correct statistical decision is - Answer- It is impossible to make a
decision about H0 without more information.
A sample of n = 25 scores produces a t statistic of t = -2.05. If the researcher is using a
two-tailed test with α = .05, the correct statistical decision is - Answer- he researcher
must fail to reject the null hypothesis with either α = .05 or α = .01
The results of a hypothesis test are reported as follows: t(29) = 2.70, p < .05. Based on
this report, how many individuals were in the sample? - Answer- 30
As sample variance increases, what happens to measures of effect size such as r2 and
Cohen's d - Answer- They tend to decrease
Which of the following is a major difference between a hypothesis test with the t statistic
formula and the test with a z-score? - Answer- You must calculate the sample variance
(or standard deviation) for the t statistic but not for the z-score. You use the unit normal
table to find critical values for the z-score test but not for the t test. You must know the
population variance (or standard deviation) for the z-score but not for the t statistic.
On average, what value is expected for the t statistic when the null hypothesis is true? -
Answer- 0
What is measured by the estimated standard error, sM? - Answer- How much difference
is reasonable to expect between a sample mean and the population mean
A sample of n = 25 individuals is selected from a population with µ= 80, and a treatment
is administered to the sample. Which set of sample characteristics is most likely to lead
to a decision that there is a significant treatment effect? - Answer- M = 90 and small
sample variance
What is the sample variance and the estimated standard error for a sample of n = 4
scores with SS = 300 - Answer- s2 = 100 and sM = 5
With α= .01, what is the critical t value for a one-tailed test with n = 30 - Answer- t =
2.462
A sample has a mean of M = 39.5 and a standard deviation of s = 4.3. In a two-tailed
hypothesis test with α= .05, this sample produces a t statistic of t = 2.14. Based on this
information, the correct statistical decision is - Answer- It is impossible to make a
decision about H0 without more information.
A sample of n = 25 scores produces a t statistic of t = -2.05. If the researcher is using a
two-tailed test with α = .05, the correct statistical decision is - Answer- he researcher
must fail to reject the null hypothesis with either α = .05 or α = .01
The results of a hypothesis test are reported as follows: t(29) = 2.70, p < .05. Based on
this report, how many individuals were in the sample? - Answer- 30
As sample variance increases, what happens to measures of effect size such as r2 and
Cohen's d - Answer- They tend to decrease
