Question

A psychologist was interested in knowing whether male heroin addicts' assessments of self-worth differ from the mean (=48.6) of the general male population. A sample of 25 heroin addicts gives: mean = 44, standard deviation = 6. Do the data indicate a difference in assessment of self-worth between male heroin addicts and general male population? Test using α = 0.01. Assume that the normal distribution assumption is satisfied for this sample.

Answer 1

H0:Null Hypothesis: = 48.6

HA: Alternative Hypothesis: 48.6

SE =s/

= 6/ = 1.20

Test statistic is:

t = (44 - 48.6)/1.20 = - 3.8333

= 0.01

ndf = 15 - 1 = 24

From Table, critical values of t = 2.7969

Since the calculated value of t = - 3.8333is less than critical value of t = - 2.7969, the difference is significant. Reject null hypothesis.

Conclusion:
The data indicate a difference in assessment of self - worth between male heroin addicts and general male population.