Question

Assume that females have pulse rates that are normally distributed with a mean of 74.0 beats per minute and a standard deviation of 12.5 beats per minute.

(a) If 1 adult female is randomly selected, find the probability that her pulse rate is less than 80 beats per minute. (Round your answer to 4 decimal places)

(b) If 16 adult females are randomly selected, find the probability that they have pulse rates with a mean less than 80 beats per minute. (Round your answer to 4 decimal places)

Answer 1

This is a normal distribution question with

a) x = 80
P(x < 80.0)=?
The z-score at x = 80.0 is,

z = 0.48
This implies that
P(x < 80.0) = P(z < 0.48) = 0.6844
b) Sample size (n) = 16
Since we know that

P(x < 80.0)=?
The z-score at x = 80.0 is,

z = 1.92
This implies that
P(x < 80.0) = P(z < 1.92) = 0.9726
PS: you have to refer z score table to find the final probabilities.
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