Question

7. The weights of a certain brand of candies are normally distributed with a mean weight of 0.8551 g and a standard deviation of 0.0521 g. A sample of these candies came from a package containing 446 candies, and the package label stated that the net weight is 380.7 g.​ (If every package has 446 candies, the mean weight of the candies must exceed 308.7/446 = 0.8536 g for the net contents to weigh at least 380.7 g.)

b. If 446 candies are randomly​ selected, find the probability that their mean weight is at least 0.8536 g.

The probability that a sample of 446 candies will have a mean of 0.8536 g or greater is

​(Round to four decimal places as​ needed.)

9. Women have pulse rates that are normally distributed with a mean of 76.5 beats per minute and a standard deviation of 11.5 beats per minute. Complete parts a through c below.

b. A doctor sees exactly 45 patients each day. Find the probability that 45 randomly selected women have a mean pulse rate between 65 and 89 beats per minute.

The probability is

​(Round to four decimal places as​ needed.)

Answer 1

in a z normal distribution we have z=