The Head Circumference Is Measured for 25 Girls and Their

Multiple Choice

The head circumference is measured for 25 girls and their younger twin sisters. The mean of the older twin girls was 50.23 cm and the mean of the younger twins was 49.96 cm. The standard deviation of the differences was 1 cm. Is this difference significant at a significance level of 5%?

A) Yes, because t = 1.35 and the p-value < 0.10.
B) Yes, because t = 6.25 and the p-value < 0.10.
C) No, because t = 1.35 and the p-value > 0.10.
D) No, because t = 0.27 and the p-value > 0.10.