Only do graph 38

Finding Standard Deviation from a Frequency Distribution. In Exercises 37-40, refer to the frequency distribution in the given exercise and find the standard deviation by using the formula below, where x represents the class midpoint, f represents the class frequency, and n represents the total number of sample values. Also, compare the computed standard deviations to these standard deviations obtained by using Formula 3-4 with the original list of data values: (Exercise 37) 11.5 years; (Exercise 38) 8.9 years; (Exercise 39) 59.5; (Exercise 40) 65.4. Standard deviation for frequency distribution n [ E(f . x2) ] - [E(f. x) 12 S n(n - 1) 37. Age (yr) of Best Actress 38. Age (yr) of When Oscar Was Won Frequency Best Actor When 20-29 29 Oscar Was Won Frequency 30-39 34 20-29 40-49 14 30-39 28 50-59 3 40-49 36 60-69 5 50-59 15 70-79 1 60-69 6 80-89 1 70-79 1