# math

posted by devon

A fitness company surveyed the weights of its 90 costumers. Assume that the weights are normally distrubted with a mean of 162 lbs and a standard deviation of 3.5 lbs. If you select one of its costumers randomly, what is the probability that the costumer's weight is
a) more than 162 lbs?
b) more than 155 lbs?
c) less than 172.5 lbs?
d) between 158.5 lbs and 169 lbs?

1. drwls

a) 50%
b) 97.7%
c) 99.9%
d) 81.9%

These answers were obtained using the normal disribution calculation tool at

I did not make use of the fact that the mean and standard deviation were obtained from 90 samples. I assumed 162 was the true mean and 3.5 was the true std deviation.

## Similar Questions

1. ### math

A fitness company surveyed the weights of its 90 costumers. Assume that the weights are normally distrubted with a mean of 162 lbs and a standard deviation of 3.5 lbs. If you select one of its costumers randomly, what is the probability …
2. ### statistics

The weights of steers in a herd are distributed normally. The standard deviation is 200 lbs and the mean steer weight is 1200 lbs. Find the probability that the weight of a randomly selected steer is less than 1560 lbs. (Round your …
3. ### statistics

Based on data from the National Health and Nutrition Examination Survey assume that the weights of men are normally distributed with a mean of 170 lbs. and a standard deviation of 30lbs. a. Find the probability that a man randomly …
4. ### Statistics

Assume the weights of men are normally distributed having a mean of 185 lbs and a standard deviation of 17 pounds. A. Calculate the probability a randomly selected man weights less than 225 lbs B. Approximately 72% of men’s weights …
5. ### Statistics

In the library on a university campus, there is a sign in the elevator that indicates a limit of 16 people. in addition there is a weight limit of 2500 lbs. assume that the average weight of students, faculty, and staff on campus is …
6. ### Statistics

In the library on a university campus, there is a sign in the elevator that indicates a limit of 16 people. in addition there is a weight limit of 2500 lbs. assume that the average weight of students, faculty, and staff on campus is …
7. ### Statistics

The weights of the fish in a certain lake are normally distributed with a mean of 15lbs. and standard deviation of 6lbs. If a sample of 5 fish are taken from the lake, find the probability their means weights are between 12.6 lbs. …
8. ### Statistics

A company that produces rivets used by commercial aircraft manufactures knows that the shearing strength (force required to breaking) of its rivets is a major concern. The company believes the shearing strength of its rivets is normally …
9. ### statistics

Case Study Chapter 6 and 7 FOR FULL CREDIT SHOW EQUATIONS USED AND WORK. ELEVATOR CAPACITY: Suppose an elevator has a maximum capacity of 16 passengers with a total weight of 2500 lbs. The mean weight of females is less than the mean …
10. ### Math

The weights of all one hundred (100) 9th graders at a school are measured, and it is found that the mean of all the measurements is 100 lbs., with a standard deviation of 15 lbs.   Explain how you would use this information to determine …

More Similar Questions