Anonymous

# A normal population has a mean of 64 and a standard deviation of 13. You select a random sample of 9.?

Compute the probability that the sample mean is: (Round your z values to 2 decimal places and final answers to 4 decimal places):

(a) Greater than 66.

Probability:

(b) Less than 62.

Probability:

(c) Between 62 and 66.

Probability:

Update:

(I am able to find the z values, but I am getting lost when it comes to the rest of the calculations.)

### 2 Answers

Relevance

- Mike GLv 74 months ago
μ = 64 and σ = 13

n = 9 so √n = 3

x̅ = Sample mean

a) z(x̅=66) = (66-64)/(13/3)

= 0.4615

From the z-tables

P(z>0.4615) = 0.3228

b) z(x̅=62) = (62-64)/(13/3) = -0.4615

P(z<-0.4615) = 0.3228

c) P(-0.4615<z<0.4615) = 0.3544

- STEPHENLv 74 months ago
Do your own homework. If you don't understand it talk to your teacher. Me doing it for you won't teach you anything.

Still have questions? Get answers by asking now.