A random sample of 122 delinquent boys was selected and randomly divided into two groups. The researcher was interested in discovering whether a six-week, nondirective, individual therapy program would affect levels of measured anxiety. The boys in Group 1 all received the therapy whereas those in Group 2 did not. Both groups were then given an anxiety-level test (high scores indicating higher levels of anxiety).

The data were as follows:

Group 1 Group 2 m1 = 98.06 m2 = 102.35 n1 = 61 n2 = 61 SEm1 = 1.98 SEm2 = 2.02

a. Calculate the standard error of difference.

b. Find the t ratio.

c. Do you reject (fail to accept) the null hypothesis?

d. Is the difference significant?

e. What type of research is this, post facto or experimental?

f. Identify both the IV and DV.