Question

Ms. Lisa Monnin is the budget director for Nexus Media Inc. She would like to compare the daily travel expenses for the sales staff and the audit staff. She collected the following sample information.

Sales ($)	129	137	142	122	137	145
Audit ($)	128	128	128	140	148	110	132

At the 0.100 significance level, can she conclude that the mean daily expenses are greater for the sales staff than the audit staff?

1. State the decision rule. (Round your answer to 3 decimal places.)

2. Compute the pooled estimate of the population variance. (Round your answer to 2 decimal places.)

3. Compute the test statistic. (Round your answer to 3 decimal places.)

4. State your decision about the null hypothesis. Do not reject H₀: μ_s ≤ μ_a or Reject H₀: μ_s ≤ μ_a

5. Estimate the p-value: Between 0.20 And 0.25

• Between 0.001 And 0.005

• Between 0.005 And 0.01

• Between 0.01 And 0.025

Answer 1

Ans:

	Sales	Audit
1	129	128
2	137	128
3	142	128
4	122	140
5	137	148
6	145	110
7		132
mean	135.333	130.571
std. dev.	8.501	11.816

a)df=6+7-2=11

Criitcal t value=1.363

Reject H0,if t>1.3631

b)Pooled variance=((6-1)*8.501^2+(7-1)*11.816^2)/(6+7-2)=109.00

c)

Test statistic:

t=(135.333-130.571)/SQRT(109.0038*((1/6)+(1/7)))

t=0.820

d)

Do not reject H0: μs ≤ μa

e)

p-value=TDIST(0.820,11,1)=0.2148

Between 0.20 And 0.25