Question

An average department store sells 200 men's suits per year. The men's suit departments at a particular national chain of stores claim that they more than the industry average. In a sample of 40 stores, they sold, on the average, 220 suits per year with a standard deviation of $40. What is the test value for this hypothesis? 1) 0.08 2) 0.50 3) 1.83 4) 3.16

Answer 1

Answer:

4) 3.16

Explanation:

Since we are comparing one sample mean with the population mean and the population standard deviation is unknown, the t-test for One Population Mean will be used.

The t statistic is obtained using the formula,

$t=\frac{\overline{X}-\mu_0}{s/ \sqrt{n}}$

$t=\frac{220-200}{40/\sqrt{40}}$

$t=3.1623$

Answer:

3) 2.552

Explanation:

The t critical value is obtained from the t critical value table for the significance level = 0.02, the degree of freedom = 18, and for two-tailed distribution.

$t_c=t_{\alpha/2,df}=t_{0.02/2,18}=t_{0.01,18}=2.5524$

(In excel use function =T.INV.2T(0.02,18))