The next three questions refer to the following scenario: in a study of parents' perceptions of their children's size, researchers kaufman et al. (current biology, 2013) asked parents to estimate their youngest child's height. the researchers hypothesized that parents tend to underestimate their youngest child's size because the youngest child is the baby of the family and everybody else in the family appears bigger compared to the baby. the sample of 39 parents who were surveyed underestimated their youngest child's height by 7.50 cm, on average; the standard deviation for the difference in actual heights and estimated heights was 7.20 cm and the data is not strongly skewed. which of the following is an appropriate null hypothesis for this