The head circumference is measured for 25 girls and their twin sisters. What is the value of the multiplier t* for a 90% confidence interval for the difference in mean head circumference between girl twins?
A) 1.68
B) 2.02
C) 1.71
D) 2.06

Question

Quizplus · Accepted Answer

The correct multiplier t* for a 90% confidence interval when dealing with paired data (such as twins) and a sample size of 25 pairs is found using the t-distribution with n-1 degrees of freedom (here, 24). The value closest to the appropriate t* for a 90% confidence level in the options given is 1.71.

The Head Circumference Is Measured for 25 Girls and Their