Question 400989
The production manager at Bellevue Steel, a manufacturer of wheelchairs, wants to perform a second analysis of the number of defective wheelchairs produced on the day shift and afternoon shift. A sample of the production from 6 day shifts and 8 afternoon shifts revealed the following number of defects. 
At the 0.10 significance level, is there a difference in the mean number of defects per shift? 
Day 10 9 6 6 4 9
Afternoon 8 10 7 5 8 10 5 6 
1. State the null and alternate hypotheses. 
Ho: u1-u2 = 0
Ha: u1-u2 is not equal to 0
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Run a two-sample T-test.
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x-bar1 = 7.6 and x-bar2 = 7.375
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2. What is the decision rule? 
Reject Ho if the ts is < -1.89 or > +1.89
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3. What is the value of the test statistic?
t = 0.1697
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4. What is your decision regarding the null hypothesis? 
Fail to reject Ho.
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5. What is the p-value?
P-value = 2*P(t > 0.1697 when df=7)  
p = 0.87
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6. Interpret the result.
The test shows strong evidence that the means are
statistically the same at the 10% significance level.
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Cheers,
Stan H.
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