A researcher decides to analyze the effects of nutrition onpersonality. He collects 7 pairs of identical twins and randomlyassigns one twin from each pair to a controlled diet condition. Thetwins assigned to the other condition are allowed to eat whateverthey please. The following are scores on a standardized personalityinventory:
Personality inventory scores for twins in controlled dietcondition:
10, 9, 4, 3, 8, 6, 7
Personality inventory scores for twins in eat-what-you-wantcondition:
16, 11, 9, 4, 5, 9, 12
NOTE: The order of the scores is important here. The first scorein the controlled diet condition (10) should be paired with thefirst score from the other condition (16), etc.
Hint: This is a two-tailed test.
- Null hypothesis:
- Alternative hypothesis:
- Statistical test (be specific!):
- Significance level: alpha = .01
- degrees of freedom:
- Critical region (t-value):
- Calculated t:
- Decision:
