Question

Suppose you do an analysis of the starting salaries of 100 recent Lehman graduates. You find that the average starting salary is $60,000 with a standard deviation of $5,000.
a. Find the 90% critical values.
b. Find the 95% critical values.

Answer 1

Answer:

a) (59180,60820)

b) (59020,60980)        

Step-by-step explanation:

We are given the following information in the question:

Mean, μ = $60,000

Standard Deviation, σ = $5,000

Sample size, n = 100

a) 90% critical values

$\mu \pm z_{critical}\frac{\sigma}{\sqrt{n}}$

Putting the values, we get,

$z_{critical}\text{ at}~\alpha_{0.10} = 1.64$

$60000 \pm 1.64(\frac{5000}{\sqrt{100}} ) = 60000 \pm 820 = (59180,60820)$

b) 95% critical values

$\mu \pm z_{critical}\frac{\sigma}{\sqrt{n}}$

Putting the values, we get,

$z_{critical}\text{ at}~\alpha_{0.05} = 1.96$

$60000 \pm 1.96(\frac{5000}{\sqrt{100}} ) = 60000 \pm 980= (59020,60980)$