Question: 8

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.

1 2 3 4 5 6 7 8 9

Sales before: 137 152 217 279 294 299 313 351 379

Sales after: 130 149 153 265 210 272 236 317 357

Using a 5% level of significance test the hypothesis that on average sales have not decreased in the week following the publicity.