For each sample, do a test for zero correlation. (a) Use Appendix D to find the critical value of tα. (b) State the hypotheses about ρ. (c) Perform the t test and report your decision. (d) Find the critical value of rα and use it to perform the same hypothesis test.
a. r = +.45, n = 20, α = .05, two-tailed test
b. r = -.35, n = 30, α = .10, two-tailed test
c. r = +.60, n = 7, α = .05, one-tailed test
d. r = -.30, n = 61, α = .01, one-tailed test