Reyes and Asbrand (2005) also measured unhealthy fantasy behaviors in child abuse victims before and after therapy. They found that D = 2.50, s_D = 8.16, and n_D = 18. These difference scores were calculated by taking the pre-therapy scores and subtracting the post-therapy scores.

a. Explain why these scores are considered paired data.

b. If we conduct a paired-samples t-test for these data, what would the null hypothesis be?

c. What would the α value be for this NHST?

d. Is a one- or a two-tailed hypothesis appropriate for this scenario? Justify your response.

e. What is the alternative hypothesis for this paired-samples t-test?

f. Calculate the degrees of freedom in this example.

g. Find the tcrit value.

h. Calculate the tobs value for the data.

i. Should you reject or retain the null hypothesis?

j. Calculate Cohen’s d for these data, using the equation in Sidebar 9.2.

k. Find a p-value for these data.