Apsychologist is investigating the hypothesis that children who grow up as the only child in the household are more introvert than those who grow up in larger families. a sample of n = 30 only children (ie, who do not have siblings) is obtained and each child is given a standardized personality test. lower scores on this test indicate more introvert personality. for the general population, scores follow n(μ=50, σ=15). but the mean of these 30 only children is x = 40 .

is there enough evidence that suggests those who do not have siblings are more introvert than those who have siblings? carry out a hypothesis test using α = 0.10 .
(a) state the null hypothesis and alternative hypothesis.
(b) calculate the p-value. show your steps.
(c) what is your decision regarding the two hypotheses?