Question

The resting heart rates for a sample of 15 students are recorded in the following stemplot.

A stemplot titled heart rates has values 55, 63, 65, 69, 69, 69, 69, 70, 71, 73, 73, 74, 75, 76, 77.

What is the mean resting heart rate for this sample?

66.0 beats per minute
69.0 beats per minute
69.9 beats per minute
70.0 beats per minute

Answer 1

• C) 69.9 beats per minute

Explanation:

Mean is the average.

It is calculated as:

• mean = sum of samples/ number of samples

Find it using the equation above:

• (55 + 63 + 65 + 69*4 + 70 + 71 + 73*2 + 74 + 75 + 76 + 77)/15 =
• 1048/15 =
• 69.866 ≈
• 69.9

Correct choice is C