Question

the resting heart rates for a sample of 15 students are recorded in the following stemplot. what is the mean resting heart rate for this sample? heart rates 5|5 6|3 6|5 9 9 9 9 7|0 1 3 3 4 7|5 6 7 key: 7|5 = 75 beats per minute 66.0 beats per minute 69.0 beats per minute 69.9 beats per minute 70.0 beats per minute

Explanation:

Step1: Write out all data values

The data values from the stemplot are 55, 63, 65, 69, 69, 69, 69, 70, 71, 73, 73, 74, 75, 76, 77.

Step2: Calculate the sum of data values

$55 + 63+65 + 69+69+69+69+70+71+73+73+74+75+76+77=1048$.

Step3: Calculate the mean

The formula for the mean $\bar{x}=\frac{\sum_{i = 1}^{n}x_{i}}{n}$, where $n = 15$ and $\sum_{i=1}^{n}x_{i}=1048$. So $\bar{x}=\frac{1048}{15}\approx69.9$.

Answer:

69.9 beats per minute