the life of a certain brand of car stereo is normally distributed with a mean of 5.2 years and a standard deviation of .9 year. what is the probability that a car stereo of this type chosen at random will last seven years or more

The lengths of human pregnancies are approximately normally distributed with a mean of 268 days and a standard deviation of 16 days. What is the probability that pregnancy lasts between 240 and 280 days?

A manufacturer knows that their items have a normally distributed lifespan, with a mean of 10.1 years, and standard deviation of 2.2 years.If you randomly purchase one item, what is the probability it will last longer than 16 years?

Suppose that a brand of lightbulb lasts on average 1690 hours with a standard deviation of 194 hours. Assume the life of the lightbulb is normally distributed. Calculate the probability that a particular bulb will last from 1418 to 2183 hours?

The amount of time it takes students to complete a biology exam is normally distributed with a population mean of 120 minutes and standard deviation of 30 minutes. What is the probability that 25 randomly selected students will take longer than 135 minutes?

Assume a standardized IQ test exists that possesses a normal distribution and has a mean score of 100 with a standard deviation of 10. What is the probability of selecting someone from the general population at random who would

Annual precipitation in a certain city is normally distributed with a mean of 99 inches, and a standard deviation of 18 inches. Find the probability that the mean annual precipitation during 35 randomly picked years will be less than 101.8 inches.

A particular fruit's weights are normally distributed, with a mean of 492 grams and a standard deviation of 14 grams. If you pick one fruit at random, what is the probability that it will weigh between 479 grams and 511 grams

The weights of a certain breed of dogs follow a normal distribution with a mean of 30 pounds and a standard deviation of 5 pounds. If a random sample of 25 dogs is selected, what is the probability that their average weight is between 28 and 32 pounds? The monthly returns on a stock follow a normal distribution with a mean return of 2% and a standard deviation of 4%. What is the probability that the stock has a negative return in any given month? The lifetimes of a certain brand of lightbulb are normally distributed with a mean of 1000 hours and a standard deviation of 100 hours. What is the probability that a randomly selected lightbulb will last more than 1100 hours?

A manufacturer of battery claims that the life of his batteries is approximately normally distributed with a mean life of 4 years and a standard deviation equal to one (1) year. What is the probability that the battery last more than five (5) years.