Question

The point estimate for the difference between 2 population means in independent populations is:

Select one:

a.
The difference between the 2 sample means

b.
The difference between the 2 sample standard deviations

c.
The difference between the 2 sample variances

2.

A study was conducted to investigate the effectiveness of a new client relationship management system in reducing reportable complaints. Results for randomly selected offices in the firm are shown in the table. The "before" value is matched to an "after" value. Are the complaint measurements, on average, lower after adopting the new client relationship management system? Test at a 5% significance level using the 5 step hypothesis testing approach. Establish Ha as a lower tail test.

After Data              Before Data           Difference

6.8                             6.6                             0.2

2.4                             6.5                            -4.1

7.4                             9                                -1.6

8.5                             10.3                         -1.8

8.1                             11.3                         -3.2

6.1                             8.1                            -2

3.4                             6.3                            -2.9

2                                 11.6                         -9.6

The sample mean and sample standard deviation of the differences above are: x-bar d = -3.13 and

sd = 2.91

Refer to exhibit 1. What is your business implication, given the correct result?

Select one:

a. At a 5% level of significance, from the sample data, there is sufficient evidence to conclude
that the reportable complaints, on average, are lower after adopting the new client relationship management system. The new client relationship management system appears to be effective in reducing complaints.

b. At a 5% level of significance, from the sample data, there is not sufficient evidence to conclude
that the reportable complaints, on average, are lower after adopting the new client relationship management system. The new client relationship management system appears not to be effective in reducing complaints.

c. At a 5% level of significance, from the sample data, there is sufficient evidence to conclude
that the reportable complaints, on average, are higher after adopting the new client relationship management system. The new client relationship management system appears to be effective in reducing complaints.

d. At a 5% level of significance, from the sample data, there is sufficient evidence to conclude
that the reportable complaints, on average, are higher after adopting the new client relationship management system. The new client relationship management system appears not to be effective in reducing complaints.

Answer 1

Question 1)

The point estimate for the difference between 2 population means in independent populations is:

Answer)

a.
The difference between the 2 sample means

Question 2)

Null hypothesis Ho : u1-u2 = 0

Alternate hypothesis Ha : u1 - u2 < 0

Test statistics t = (mean difference)/(s.d/√n)

t = (-3.13)/(2/91/√8) = -3.04

Degrees of freedom is = n-1 = 7

For 7 dof and -3.04 test statistics

P-value from t distribution is = 0.0094

As the obtained P-value is less than 0.05 (given significance)

We reject the null hypothesis Ho

a. At a 5% level of significance, from the sample data, there is sufficient evidence to conclude
that the reportable complaints, on average, are lower after adopting the new client relationship management system. The new client relationship management system appears to be effective in reducing complaints.