the resting heart rate for a sample of individuals are normally distributed with a mean of 67 and a standard deviation of 11. Use the 68-95-99.7 rule to find out what percentage of heart rates less than 45

Answer 1

To use the 68-95-99.7 rule, we need to calculate the z-score for a heart rate of 45.

The z-score formula is:
z = (x - μ) / σ

Where:
x = individual value
μ = mean
σ = standard deviation

Plugging in the given values, we get:
z = (45 - 67) / 11
z ≈ -2

Now, we can find the percentage of heart rates less than 45 by referring to the standard normal distribution table or using a calculator/statistical software.

Since the z-score is negative, we are interested in finding the percentage less than the given value of z. Looking up z = -2 in the standard normal distribution table, we find that the percentage is approximately 2.28%.

Therefore, approximately 2.28% of heart rates are less than 45.