In the lab tab in the data file, there is data on the IQs for first graders at a university lab school. a. Calcualte a point estimate of the mean value of IQ for the population of first graders at this school. What estimator did you use? b. Calculate a point estimate of the IW value that separates the lowert 50% of all such students from the highest 50% of students. c. Calculate a 99% confidence interval for the population mean. What sampling distribution did you use? Why? d. Test the hypothesis that this population of first graders is not smarter nor less smart than the wider population (which has average IQ equal to 100).