Ms Lisa Monnin is the budget director for Nexus Media Inc Sh

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 ($)

126

134

148

157

134

147

  Audit ($)

123

102

128

143

153

127

131

Click here for the Excel Data File

At the 0.005 significance level, can she conclude that the mean daily expenses are greater for the sales staff than the audit staff?

(a)

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

  Reject H₀ if t >

(b)

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

  Pooled variance

(c)

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

  Value of the test statistic

(d)

State your decision about the null hypothesis.

H₀ : ?_s ? ?_a

(e)

Estimate the p-value. (Round your answers to 3 decimal places.)

  p-value

Solution

(a) The degree of freedom =n1+n2-2=6+7-2=11

Given a=0.005, the critical value is t(0.005, df=11) = 3.106 (from student t table)

Reject H₀ if t >3.106

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(b) Pooled variance = 200.70

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(c)

the test statistic is

t=mean difference/(s/vn)

=1.450

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(d) So not reject Ho.

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(e) the p-value= 0.0874