2} The speeds of a random sample of 100 cars are recorded as theyr pass a highway checkpoint. The results are summarized in the frequency distribution below. Approximate the sam ple mean. Speed (mph) Cars 30-39 3 40-49 1 7 50-59 50 60-69 20 70-79 10 Suppose your hypothesis is H0 = 55. Calculate withing a confidence level of 5% if this is reasonable. Secondly give an approximate interval of a 5% confidence level. Note: Recall the fol lowing: X is the sample statistic taken from the data on the table. 11 2 M S 2 or the sample deviation is calculated by 1 n Note that the standard deviation of the statistic Of = i J1