Question

Calculate the sample standard deviation and sample variance for the following frequency distribution of heart rates for a sample of American adults. If necessary, round to one more decimal place than the largest number of decimal places given in the data.

Answer 1

Answer:

Let's complete the question using these data

Heart Rates in Beats per Minute

Class Frequency

61-66 2

67-72 11

73-78 11

79-84 3

85-90 8

Sample variance = 56.6924

Sample std dev = 7.5

Explanation:

First, let's find the average

The average

(2 x 63.5 + 11 x 69.5 + 11 x 75.5 + 3 x 81.5 + 8 x 87.5)

___________________________

(2+11+11+3+8)

2666.5

= _______

35

= 76.18571

variance = 1927.54/34

= 56.6923529

Sample variance = 56.6924

std dev = sqrt( variance)

= sqrt(56.6924)

= 7.529

Sample std dev = 7.5