Dr Kelly is a developmental psychologist who studies the eff

Dr. Kelly is a developmental psychologist who studies the effect of income on family dynamics. In one of her studies, she examined whether low SES (i.e., income below the poverty line) would affect parenting quality. To address this research question, she recruited 45 parents who are at or below the poverty line and asked them to complete the Parental Competence Scale-Revised (PCSR). On this measure, 1 indicates parents being extremely incompetent, and 7 indicates parents being extremely competent. In the general population of United States families, parents score 4.65 on this measure. Below is the data collected from the 45 parents with a child with cancer in the study conducted by Dr. Watson.

3, 1, 7, 6, 5, 4, 5, 3, 6, 5, 1, 3, 4, 2, 4, 2, 3, 4, 6, 5, 2, 4, 4, 6, 4, 1, 2, 6, 1, 6, 5, 2, 6, 6, 5, 6, 4, 3, 5, 7, 7, 3, 4, 2, 5

1. what is null hypothesis, alternative hypothesis, and critical value?

Solution

Let mu be the population mean

Null hypothesis: mu=4.65

Alternative hypothesis: mu not equal to 4.65

Assume that the significant level a=0.05

It is a two-tailed test.

The critical values are Z(0.025)= -1.96 or 1.96 (from standard normal table)