Twenty-four pairs of adult brothers and sisters were sampled at random from a population. The difference in heights, recorded in inches brother’s height minus sister’s height, was calculated for each pair. The 95% confidence interval for the mean difference in heights for all brother-and-sister pairs in this population was -0.76, 4.34. What is the margin of error for the confidence interval? 4.34 - -0.76 / 2 = 2.55