Stats Help for College-level Students

Testing a hypothesis.

A sample from a N(μ,σ2) yields data 353, 351, 351, 355. Test H0: σ = 0.7 vs. H1: σ > 0.7 at the 5% level.

Understanding what the correlation coefficient values signify.

What do the correlation coefficient values mean?

Calculating probability using mean and standard deviation. Attachment in Word.

The ages of the volunteer members of fire department are normally distributed with a mean of 36 and a standard deviation of 6. What is the probability that a member selected at random will be between the ages of 33 and 45?

Calculating the probability that a basketball player will have more free throws than his average.

A basketball player makes 80% of his free throws. If he attempts eight free throws during the next game, what is the probability that he will make more than his average?

Determining the probability of an independent event.

Events a and B are independent. P(A)=0.72 and P(A and B)=0.18 What is P(B) equal to?

Determining the relative frequency using cutpoints and a given set of data.

For the following data set, what is the relative frequency of the class with a lower cut point at 100 and upper cutpoint at 150? {0, 41, 65, 83, 103, 112, 138, 150, 178, 232}

Determining the standard deviation from a set of data.

An elf at the Keebler factory checks to see that packages of cookies are properly filled by randomly selecting six packages from a box of 50 and weighing them. He makes the following measurements in ounces: {17, 18, 18, 16, 16, 15}. What is the standard deviation?

Determining the standard deviation from a set of data.

At the end of the season, the number of wins in a softball league for each of the eight teams is: {10, 9, 5, 4, 4, 3, 3, 2} What is the standard deviation of wins?

Calculating the standard deviation given a probability distribution. Attachment in Word.

x P(X=x) (5 @ .12) (6 @ .24) (8 @ .44) (10 @ .20) What is the standard deviation of X?

Determining the probability using mean and standard deviation.

A sample of 100 is taken from a population which has a normal distribution with a mean of 80 and a standard deviation of 40. What is the probability that the sample mean is between 74 and 81 is?