Statistics and Probability Answers

A population consists of the four numbers {2, 3, 6, 9}. Consider all possible samples of size 3 can be drawn without replacement from this population. Find the following:

a. mean of the population

b. population variance 

c. standard deviation of the population

d. mean of the sampling distribution of means

e. the standard deviation of the sampling distribution of means

f. List down all the possible samples of size 3.

g. construct a sampling distribution

The average preschool cost for tuition fees last year was 17,250. The following year, 20 institutions had a mean of 16,150 and a standard deviation of 2,250 is there sufficient evidence at =0.10 level of significance to conclude that the mean cost has increased?

Find the variance of the expected value of the probability distribution, X={1, 2, 3, 4, 5} P(X)={.10, .35, .15, .23, .17}

Two coins are tossed simultaneously. The outcome of the first coin is head. Let x be a random variable that denotes the number of heads that appear. What are the possible value of x?

A golfer playing a new course encounters a hole that requires a drive of 145 yards to successfully clear a pond. She knows that her drives are normally distrib- uted with a mean of 155 yards and a standard devia- tion of 9 yards. What is the probability that after her drive her golf ball will be at the bottom of the pond? 

P ( -2.81 < z < 0 ) 

If three coins are tossed, what are the mean, variance, and standard deviation of the number of heads that occur?

Suppose two laptops are tested. Let D represent the defective laptop and N represent the non-defective laptop. If we let X be the random variable representing the number of defective laptops. What are the possible values of the random variable X? *

The shelf life of a particular dairy product is normally distributed with a mean of 12 days and a standard deviation of 3 days. What percent of the product that between 10 and 15 days?

What is the area under the normal curve that corresponds to z = 1.36?