Final answer:
The normal distribution can be used in part (b) even when the sample size is less than 30. This is because it is still a reasonable approximation for smaller sample sizes. We can assume that females have pulse rates that are normally distributed and use the given mean and standard deviation to make statistical inferences.
Step-by-step explanation:
The normal distribution can be used in part (b) even when the sample size is less than 30. This is because the normal distribution is an excellent approximation when the sample size is greater than 30, but it can still be reasonably used when the sample size is smaller.
In part (b), we are assuming that females have pulse rates that are normally distributed with a mean of μ=73.0 beats per minute and a standard deviation of σ=12.5 beats per minute. With this information, we can still use the normal distribution to make statistical inferences about the pulse rates of females.