This Question: 1 pt 1 8 of 21 (1 1 complete) Assume that for ales have pulse rat

Question

This Question: 1 pt 1 8 of 21 (1 1 complete) Assume that for ales have pulse rates that are normal y d tributed with a mean of -74 0 beats per minute and a standard de ation of-12.5 beats per minute. Complete ans a ro e be e a. If 1 adult female is randomly selected, find the probability that her pulse rate is less than 77 beats per minute The probablity is Round to four decimal places as needed.) b. If 4 adult females are randomly selected, find the probability that they have pulse rates with a mean less than 77 beats per minute. The probability is Round to four decimal places as needed.) c. Why can the normai distribution be used in part (b), even though the sample size does not exceed 30? A. Since the mean pulse rate exceeds 30, the distribution of sample means is a normal distribution for any sample size B. Since the original population has a normal distribution, the distribution of sample means is a normal distribution for any sample size c. sne te distbution is of nivduals, not sample means, the distribution is a normal distribution for any sample size. D Since the distribut on is of sample means, not individuals, the distribution is a nornal distribution for any sample size.

Explanation / Answer

a) mean = 74 , sd = 12.5
Z =(X - 74)/12.5
P(X < 77)
= P (Z<0.24)=0.5948

b) n = 4
sd(Xbar) = s/sqrt(n) = 12.5/2 = 6.25

P(Xbar < 77)
= P (Z<0.48)=0.6844

c)
optio B) is correct

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