A disabled person's acceptance of a disability is critical to the rehabilitation process. Thc Journal of Rehabilitation (Sept. 1989) published a study that investigated the relationship between assertive behavior level and acceptance of disability in 160 disabled adults.

The dependent variable, assertiveness (y), was measured using the Adult Self Expression Scale (ASES).

Scores on the ASES range from 0 (no assertiveness) to 192 (extreme assertiveness). The model analyzed was E(Y) = P,, + PIX, + P2~2 + P3~3, where xl = Acceptance of disability (AD) score x2 = Age (years)
x3 = Length of disability (years)
The regression results are shown in the table.
Independent Variable t Two-Tailed p-Value AD score (x,) 5.96 .0001 Age (x,) 0.01 .9620 Length (x3) 1.91 ,0576

a. Is there sufficient evidence to indicate that AD score is positively linearly related to assertiveness level, once age and length of disability are accounted for? Test using a = .05.

b. Test the hypothesis H,: P, = 0 against Ha: fi, f 0 Use a = .05. Give the conclusion in the words of the problem.

c. Test the hypothesis H,: /3, = 0 against Ha: P, > 0.
Use a = .05. Give the conclusion in the words of the problem.