Please work in MiniTab. Thank you. Following newspaper revelations about contami
ID: 3149857 • Letter: P
Question
Please work in MiniTab. Thank you.
Following newspaper revelations about contamination of a certain brand of meat paste the manufacturer of a rival product wants to establish whether demand for their product has been affected. The Sales Director contacts a random sample of stockists and asks them how many units were sold in the week before the publicity and how many were sold in the week following it. The results are, in thousands of units:
Stockist
Using a 5% level of significance test the hypothesis that on average sales have not decreased in the week following the publicity.
The answer is Test Statistic = -3.625 Reject Ho at the 5% level
I cant figure out how the book came to this answer.
Please work in Minitab. Thank you.
1 2 3 4 5 6 7 8 9 Sales Before 137 152 217 279 294 299 313 351 379 Sales After 130 149 153 265 210 272 236 317 357Explanation / Answer
the minitab answer
Two-Sample T-Test and CI: Sales Before, Sales After
Two-sample T for Sales Before vs Sales After
SE
N Mean StDev Mean
Sales Before 9 269.0 83.8 28
Sales After 9 232.1 78.7 26
Difference = mu (Sales Before) - mu (Sales After)
Estimate for difference: 36.9
95% lower bound for difference: -30.0
T-Test of difference = 0 (vs >): T-Value = 0.96 P-Value = 0.175 DF = 16
Both use Pooled StDev = 81.3076
(steps: enter the sample data in two different columns ->stat->basic statistics->2-sample t->select samples in different columns->select these two colums->equal variance check in -> options->alternative less than->ok->ok)
test statistics is 0.96
p-value is 0.157>0.05 then we accept H0 and claim that the sales are same as before