The owners of a small business decide to look at the mean number of customers who make a purchase in the store on days immediately following days when their radio ads are played compared to the mean for days following days when no radio ads are played. They found that for 11 days following no ads, the mean was 17.8 purchasing customers with a standard deviation of 3.5 customers. On 6 days following radio ads, the mean was 22.8 purchasing customers with a standard deviation of 2.8 customers. Test the claim, at the 0.01 level, that the mean number of customers who make a purchase in the store is lower for days following no radio ads compared to days following radio ads. Assume that the population variances are equal.

Hypotheses:

Test statistic and value: P-value:

Conclusion: