PSYC 355 Quiz 2
Question 1
2..5 pts
In general, if the variance of the difference scores increases, what will happen to the value
of the t statistic?
It will increase in magnitude (move farther toward the tail of the distribution).
It will decrease in magnitude (move toward 0 at the center of the distribution).
It will stay the same; the t statistic is not affected by the variance of the difference
scores.
It may increase or may decrease; there is no consistent relationship between variance
and the size of the t statistic.
Question 2
2..5 pts
Compared to an independent-measures design, a repeated-measures study is more likely
to find a significant effect because it reduces the contribution of variance due to
.
time-related factors
order effects
the effect of the treatment
individual differences
Question 3
2..5 pts
Assuming that other factors are held constant, which of the following would tend to increase
the likelihood of rejecting the null hypothesis?
, Decrease the sample size
Increase the sample mean difference
Increase the sample variance
None of the other 3 options would increase the likelihood.
Question 4
2..5 pts
A researcher conducts a repeated-measures study to evaluate a treatment with a sample
of n = 16 participants and obtains a t statistic of t = 1.94. The treatment is expected to
increase scores and the sample mean shows an increase. Which of the following is the
correct decision for a hypothesis test using α = .05?
Reject the null hypothesis with a one-tailed test but fail to reject with two tails
Reject the null hypothesis with either a one-tailed or a two-tailed test
Fail to reject the null hypothesis with either a one-tailed or a two-tailed test
Fail to reject the null hypothesis with a one-tailed test but reject with two tails
Question 5
2..5 pts
If a repeated-measures study shows a significant difference between two treatments with α
= .01, then what can you conclude about measures of effect size?
The value of Cohen’s d is large.
The percentage of variance explained (r ) is large.
2
Both Cohen’s d and r are large.
2
Question 1
2..5 pts
In general, if the variance of the difference scores increases, what will happen to the value
of the t statistic?
It will increase in magnitude (move farther toward the tail of the distribution).
It will decrease in magnitude (move toward 0 at the center of the distribution).
It will stay the same; the t statistic is not affected by the variance of the difference
scores.
It may increase or may decrease; there is no consistent relationship between variance
and the size of the t statistic.
Question 2
2..5 pts
Compared to an independent-measures design, a repeated-measures study is more likely
to find a significant effect because it reduces the contribution of variance due to
.
time-related factors
order effects
the effect of the treatment
individual differences
Question 3
2..5 pts
Assuming that other factors are held constant, which of the following would tend to increase
the likelihood of rejecting the null hypothesis?
, Decrease the sample size
Increase the sample mean difference
Increase the sample variance
None of the other 3 options would increase the likelihood.
Question 4
2..5 pts
A researcher conducts a repeated-measures study to evaluate a treatment with a sample
of n = 16 participants and obtains a t statistic of t = 1.94. The treatment is expected to
increase scores and the sample mean shows an increase. Which of the following is the
correct decision for a hypothesis test using α = .05?
Reject the null hypothesis with a one-tailed test but fail to reject with two tails
Reject the null hypothesis with either a one-tailed or a two-tailed test
Fail to reject the null hypothesis with either a one-tailed or a two-tailed test
Fail to reject the null hypothesis with a one-tailed test but reject with two tails
Question 5
2..5 pts
If a repeated-measures study shows a significant difference between two treatments with α
= .01, then what can you conclude about measures of effect size?
The value of Cohen’s d is large.
The percentage of variance explained (r ) is large.
2
Both Cohen’s d and r are large.
2
