A consumer advocacy group tested the "on-air" lifetimes of a random sample of 198 cell phone batteries. The mean lifetime was 3.8 hours with a standard deviation of 0.1 hours. The lifetimes are approximately bell-shaped. Estimate the number of batteries with lifetimes between 3.7 hours and 3.9 hours.

Dimitri used a coupon that saved him 80 percent, or $6.87. he paid $34.35 for the items.dimitri used a coupon that saved him 80 percent, or $27.48. he paid $34.35 for the items.dimitri used a coupon that saved him 80 percent, or $6.87. the price of the items before the discount was $34.35.dimitri used a coupon that saved him 80 percent, or $27.48. the price of the items before the discount was $34.35.