A sample is selected from a population with = 70, and a treatment is administered to the sample. After treatment, the sample mean is M = 74, and Cohen's d is d = 1.00 . What is the value of the sample variance?
a. s2 = 2
b. s2= 4
c. s2 = 16
d. It is impossible to determine the sample variance without more information.
Question 2A sample is selected from a population with = 46, and a treatment is administered to the sample. After treatment, the sample mean is M = 48 with a sample variance of s2 = 16 . Based on this information, what is the value of Cohen's d?
a. d = 0.125
b. d = 0.25
c. d = 0.50
d. Cohen's d cannot be computed without knowing the sample size.
Question 3If other factors are held constant, how does sample size influence the likelihood of rejecting the null hypothesis and measures of effect size such as r2 and Cohen's d?
a. A larger sample increases both the likelihood and measures of effect size.
b. A larger sample increases the likelihood but has little influence on measures of effect size.
c. A larger sample decreases the likelihood but has little influence on measures of effect size.
d. A larger sample decreases both the likelihood and measures of effect size.
Question 4Two samples from the same population both have M = 84 and s2= 20, but one sample has n = 10 and the other has n = 20 scores. Both samples are used to evaluate a hypothesis stating that = 80 and to compute Cohen's d. How will the outcomes for the two samples compare?
a. The larger sample is more likely to reject the hypothesis and will produce a larger value for Cohen's d.
b. The larger sample is more likely to reject the hypothesis, but the two samples will have the same value for Cohen's d.
c. The larger sample is less likely to reject the hypothesis and will produce a larger value for Cohen's d.
d. The larger sample is less likely to reject the hypothesis, but the two samples will have the same value for Cohen's d.
Question 5A researcher selects a sample from a population with = 30 and uses the sample to evaluate the effect of a treatment. After treatment, the sample has a mean of M = 32 and a variance of s2 = 6 . If Cohen's d is used to measure the size of the treatment effect, which of the following would have no effect on the value of Cohen's d?
a. Increase the sample size
b. Increase the sample mean
c. Increase the sample variance
d. All of the other options will influence the value of Cohen's d.
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