A
psychologist is investigating the hypothesis that children who grow up as the
only child in the household develop different personality characteristics than
those who grow up in larger families. A sample of n = 30 only children is
obtained and each child is given a standardized personality test. For the
general population, scores on the test from a normal distribution with a mean
of ? = 50 and a standard deviation of ? = 15. If the mean for the sample is M =
58, can the researcher conclude that there is a significant difference in
personality between only children and the rest of the population? Use a
two-tailed test with ? = .05.
H0: The personality
scores for the children from single child households will be
(different/no different) ______
than the population mean of ? = 50.
H1: The personality
scores for the children from single child households will be
(different/no different) _____
than the population mean of ? = 50.
Each critical region consists of a proportion
of sample means equal to(3
decimal places required) ______,
which correspond to z-scores beyond the critical boundaries of(2 decimal places required) z = ±______.
The expected value of M is(no decimals required) _____, and the standard error of the
mean is(3
decimals required) _______.
The z-score corresponding to our sample mean is(2 decimal required) _____, which is located(within/outside) ______ the boundaries of the critical
region.
The effect size for our study has a Cohen’s d
value equal to(3
decimals required) ______, which is a(small/medium/large) ______ effect.
Write a sentence describing the outcome of the
hypothesis test from the previous question as it would appear in a research
report.Note:
Correct answers must include all of the following: the conclusion of the test
in terms of the IV and DV, test statistic, p-value, and the measure and value
of the effect size.
