Crawling Babies. The following data represent the age in weeks at which babies first crawl based on a survey of 12 mothers conducted by Essential Baby.

30 44 52 39 35 26

37 47 26 39 28 56

a) Draw a normal probability plot and boxplot to determine if it is reasonable to conclude the data come from a population that is normally distributed. Copy/paste the graphs into your solution along with an explanation of why or why not.

b) Construct a 95% confidence interval for the mean age at which a baby first crawls.

c) Interpret your confidence interval in part "b". (I am ____% confident that ______).

d) Sample Size: How large a sample size is needed to estimate the mean age in weeks at which a baby first crawls within 1.5 weeks with 95% confidence?