Exam 7: Continuous Probability Distributions

The z-scores for X values greater than the mean are negative.

The employees of Cartwright Manufacturing are awarded efficiency ratings. The distribution of the ratings approximates a normal distribution. The mean is 400, the standard deviation 50. What is the area under the normal curve between 400 and 482?

The weekly mean income of a group of executives is $1,000 and the standard deviation of this group is $100. The distribution is normal. What percent of the executives have an income of $925 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 is the probability that a student scored greater than 65?

What is the area under the normal curve between z = 0.0 and z = 1.79?

For a uniformly distributed random variable, x, P(x) = 1/(b - a).

A large manufacturing firm tests job applicants. 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 sixth percent of the distribution. What is the lowest score a new hire must earn to qualify for a responsible position?

Two business major students, in two different sections of an economics class, were comparing test scores. The following shows the sections' mean and standard deviation. The student in section 2 scored 75. The student's z score would be _____.

Which of the following is true regarding the normal distribution?

What is special about the standard normal distribution?

The mean of a normal distribution is 400 pounds. The standard deviation is 10 pounds. What is the probability of a weight between 415 pounds and the mean of 400 pounds?

What is the probability that z is between 0.0 and 2.0?

The standard deviation of any uniform probability distribution is ____________.

In a uniform distribution, with a minimum, a, and maximum, b, the probability that the random variable, x, is between a and (b - a)/2 is ___________.

The formula used to compute the standard deviation is ________.

The annual income for a sample of 500 part-time students is normally distributed with a mean income of $30,000 and a standard deviation of $3,000. The income range that separates the top 25% from the lower 75% is __________.

A z-value measures the distance between an outcome, x, and its population mean in terms of the number of _____________________.

Describe the normal distribution.

The formula to convert any normal distribution for a random variable, x, to the standard normal distribution is ____________.

The time to fly between New York City and Chicago is uniformly distributed with a minimum of 120 minutes and a maximum of 150 minutes. What is the distribution's standard deviation?