Research suggests that identical twins have many similarities, such as body weights, even as adults. A sample of ten sets of identical twins were weighed and had their weights recorded in kilograms. The researcher wishes to test whether there is a statistically significant difference in adult weight between first born and second born identical twins.

Given the design of the study and the question of interest, which of the following 4 computer outputs is relevent to use?

A. Paired T-Test and Cl

Sample N Mean StDev SE Mean

First-Born 10 77.59 23.38 7.39
Second-Born 10 78.02 17.36 5.49
Difference 10 -0.43 11.83 3.74

95% upper bound for mean difference: 6.43

T-Test of mean difference = 0 (vs < 0): T-value = -0.12 P-value = 0.455

B. Two-Sample T-Test and Cl

Sample N Mean StDev SE Mean

First-Born 10 77.6 23.4 7.4
Second-Born 10 78.0 17.4 5.5
Difference = mu (First=Born) - mu (Second-Born)

Estimate for difference: -0.43

95% upper bound for difference: 15.64

T-Test of difference: 0 (vs <): T-value = -0.05 P-value = 0.482 DF = 16

C. Paired T-Test and Cl

Sample N Mean StDev SE Mean

First-Born 10 77.59 23.38 7.39
Second-Born 10 78.02 17.36 5.49
Difference 10 -0.43 11.83 3.74

95% Ci for mean difference: (-8.89, 8.03)

T-Test of mean difference = 0 (vs not = 0): T-value = -0.12 P-value = 0.911

D. Two-Sample T-Test and Cl

Sample N Mean StDev SE Mean

First-Born 10 77.6 23.4 7.4
Second-Born 10 78.0 17.4 5.5
Difference = mu (First=Born) - mu (Second-Born)

Estimate for difference: -0.43

95% CI for difference: (-19.95, 19.09)

T-Test of difference: 0 (vs not =): T-value = -0.05 P-value = 0.963 DF = 16