Question

Suppose you run a software company and you want to determine if there is a difference between the 'debugging unit' (population 1) and 'after sales services unit' (population 2) by considering the return on investment for each unit. you have acsess to information from a random survey which is done for 24 companies for population 1 which reveals that the average return on investment (ROI) for each dollar you invest is.12, while for population, the survey is performed on 30 companies and the average ROI is found to be .30. You also know from the previously published results that the standard deviation for any ROI in the software industry is .25 What is the value of the test statistic for your research hypothesis?
a. -1.3145.
b. -1.2728.
c. -2.3738.
d. -2.2411.
e. -2.6291.

Answer 1

Answer:

e. -2.6291.

Explanation:

from the information available in this question,

mean x₁ = 0.12

mean x₂ = 0.30

n₁ = 24

n₂ = 30

n1 = 24 < 30

n₂ = 30 <= 30

therefore we would be solving this using the t test.

we have

$t =\frac{x_{1-x_{2} } }{s} *\sqrt{\frac{n1n2}{n1+n2} }$

inserting values whe have:

$t=\frac{0.12-0.30}{0.25} *\sqrt{\frac{24*30}{24+30} }$

$t = -0.72 *\sqrt{13.33333}$

$t=-0.72*3.6514836$

$t=-2.629067947$

this is approximately

$-2.6291$

therefore option e answers this question.