A factory produces a component used in manufacturing computers, each of which is tested prior to shipment to determine whether or not it is defective. In a random sample of 300 units, 12 were found to be defective.

a) Estimate, with 99% confidence, the true proportion of defective components produced by this factory.

b)A company attempts to evaluate the potential for a new bonus plan by selecting a random sample of five salespersons to use the bonus plan for a trial period. Weekly sales volumes before and after implementing the bonus plan are shown below.

Salesperson	1	2	3	4	5
Before	12	11	19	15	18
After	15	13	18	18	20

Test at a 10% significance level, to see if the bonus plan will result in an increase in the mean weekly sales.