Exam 7: Continuous Probability Distributions

The average score of 100 students taking a statistics final was 70 with a standard deviation of 7. Assuming a normal distribution, what is the probability that a student scored 90 or higher?

To apply the normal approximation to a binomial distribution what must be true? ________________

What is the area under the normal curve between z = -1.0 and z = -2.0?

Suppose a tire manufacturer wants to set a mileage guarantee on its new XB 70 tire. Tests revealed that the tire's mileage is normally distributed with a mean of 47,900 miles and a standard deviation of 2,050 miles. The manufacturer wants to set the guaranteed mileage so that no more than 5 percent of the tires will have to be replaced. What guaranteed mileage should the manufacturer announce?

A major credit card company has determined that customers charge between $100 and $1100 per month. Given that the average monthly amount charged is uniformly distributed, what percent of monthly changes are between $311 and $889? ________

A study conducted by a local tennis center revealed that 25 percent of its new members have novice level tennis skills. A membership drive in a metropolitan area resulted in 500 new members. What is the mean and standard deviation to apply the normal approximation to the binomial?

The weight of a bag of corn chips is normally distributed with a mean of 22 ounces and a standard deviation of ½ ounces. What is the probability that a bag of corn chips weighs between 20.75 and 23.25 ounces? _____

If an average of 12 customers is served per hour, what is the probability that the next customer will arrive in 6 minutes or less?

The average score of 100 students taking a statistics final was 70 with a standard deviation of 7. Assuming a normal distribution, what test score separates the top 5% of the students from the lower 95% of students?

A large manufacturing firm tests job applicants who recently graduated from college. The test scores are normally distributed with a mean of 500 and a standard deviation of 50. Management is considering placing a new hire in an upper level management position if the person scores in the upper 6 percent of the distribution. What is the lowest score a college graduate must earn to qualify for a responsible position?

The weight of a bag of corn chips is normally distributed with a mean of 22 ounces and a standard deviation of ½ ounces. What is the probability that a bag of corn chips weighs more than 23 ounces? _____

The exponential distribution can be used to predict ________.

The mean of a normal probability distribution is 500 and the standard deviation is 10. About 95 percent of the observations lie between what two values?

Non-stop Airlines determined that the mean number of passengers per flight is 152 with a standard deviation of ten passengers. Practically all flights have between 142 and 162 passengers.

The normal distribution can be used to approximate a binomial distribution when n $\pi$ is less than 5.

The standard normal probability distribution is unique because it has:

About what percent of the area under the normal curve is within plus two and minus two standard deviation of the mean? _______

A "continuity correction factor" is used to compute probabilities when using the normal distribution to approximate the binomial distribution.

What proportion of the area under a normal curve is to the right of z = -1.21? ________

A major credit card company has determined that customers charge between $100 and $1100 per month. Given that the average monthly amount charged is uniformly distributed, what percent of monthly charges are between $600 and $889? ____________