Math 143 C/E
Probability and Statistics
Spring, 2001

Test of Significance: Alkaline Batteries

The reputation (and hence sales) of many businesses can be severely damaged by shipments of manufactured items that contain a large percentage of defectives. For example, a manufacturer of alkaline batteries may want to be reasonably certain that fewer than 5% of its batteries are defective. Suppose 300 batteries are randomly selected from a very large shipment. Each is tested, and 10 defective batteries are found. Does this provide sufficient evidence for the manufacturer to conclude that the fraction defective in the entire shipment is less than 5%?

(Notes:

  1. Show the P-value to be 0.0885 and draw some conclusion.
  2. If you don't know what you're doing, try constructing a 80% confidence interval for the proportion of defective batteries in the shipment.


Last Modified: