Answer :
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

