Statistics and Probability Answers

In how many different ways can 15 tickets to a football game be distributed among a class of 30 students if each students gets at most one ticket?

How many different four letter english words(with or without meaning) can be written using distinct letters from alphabet?

A manufacturer of ball bearings claims that this product has a mean weight of 5.02 g and a standard deviation of 0.30 g. What is the probability that a random sample of 100 ball bearings will have combined weight:

a. between 496 g and 500 g?

b. more than 510 g?

The average number of driving miles before a certain kind of tire begins to show wear is 16,800 miles with a standard deviation of 3,300 miles. A car rental agency buys 36 of these tires for replacement purposes and puts each one on a different car:

a. What is the probability that the 36 tires will average less than 16,000 miles until they begin to show wear?

b. What is the probability that the 36 tires will average more than 18,000 miles until they begin to show wear?

In a study of the life expectancy of 400 people in a certain geographic region, the mean age of death was 70 years, and the standard deviation was 5.1 years. If a sample of 50 people from this region is selected, what is the probability that the mean life expectancy will be less than 68 years?

A game in a state lottery selects four numbers from a set of numbers,{0,1,2,3,4,5,6,7,8,9} with no number being repeated. how many possible groups of four numbers are possible?

The average public High School gas 468 students with a standard deviation of 87:

a. If a public school is selected, what is the probability that the number of students enrolled is greater than 400?

b. If a random sample of 38 public elementary schools is selected, what is the probability that the number of students enrolled is between 445 and 485?

The average cholesterol content of a certain canned goods is 215 milligrams, and the standard deviation is 15 milligrams. Assume the variable is normally distributed:

a. If a canned goods is selected, what is the probability that the cholesterol content will be greater than 220 milligrams?

b. If a sample of 25 canned goods is selected, what is the probability that the mean of the samle will be larger than 220 milligrams?

A manufacturer of light bulbs produces bulbs that last a mean of 950 hours with a standard variation of 120 hours. What is the probability that the mean life-time of a random sample of 10 of these bulbs is less than 900 hours?

A random sample of n = 60 measurements is obtained from a population with μ = 192 and σ 43. Describe the sampling distribution for the sample means by computing the μ_x and σ_x.