Question

A normally distributed population has a mean of 500 and a standard deviation of 60. a. Determine the probability that a random sample of size selected from this population will have a sample mean less than . 9 455 b. Determine the probability that a random sample of size selected from the population will have a sample mean greater than or equal to . 25 532 a. P x < 455 = (Round to four decimal places as needed.) b. P x ≥ 532 = (Round to four decimal places as needed

Please solve in an excel!

I need the answer with in an hour

Answer 1

Let ,

a) Since , n=9

Therefore , the sampling distribution of the sample mean is approximately normaly distributed with sample mean and sample standard deviation

Now ,

; The Excel function is , =1-NORM.DIST(2.25,0,1,TRUE)

b) Since , n=25

Therefore , the sampling distribution of the sample mean is approximately normaly distributed with sample mean and sample standard deviation

Now ,

; The Excel function is , =1-NORM.DIST(2.67,0,1,TRUE)