### Home > INT3 > Chapter 5 > Lesson 5.1.2 > Problem 5-36

Aurora is starting a fitness program and she needs to determine an easy measure of fitness to gauge her improvement. She decides that using resting heart rate would be helpful. Assume that the resting heart rate of women Aurora’s age is approximately normally distributed with a mean of 74 beats per minute (bpm) with a standard deviation of 5 bpm. Homework Help ✎

Aurora finds a chart that says resting heart rates between 70 and 79 (inclusive) are considered average for women her age. What proportion of her peers should she expect to be in the average range?

The chart also claims that resting heart rate of 66 or less indicates excellent fitness. What portion of her classmates would she expect to be in excellent shape?

Aurora’s fitness program lowers her resting heart rate by 4 bpm. If every woman lowers her heart rate by 4 bpm, what will be the

*increase*in the proportion of women now classified as being in excellent shape?

normalcdf(70, 79, mean, standard deviation)

normalcdf(-10^99, 66, mean, standard deviation)

What would the new mean be?

Repeat your steps in part (b) with the new mean.