Exam 4: Probability Distributions

If you want to determine the likelihood that a particular event will occur, you should calculate the ______.

You would expect that 100% of the data would fall under the curve in a given probability distribution.

The 80th percentile is most closely associated with which of the following z-scores?

44.04% of scores in a normal distribution fall above what z-score?

What proportion of scores fall below z = 1.5 in normally distributed data?

If x̄ = 1 and s² = 9 and scores are normally distributed, what is the percentile rank of x = 4?

The only difference between the z-score formula for samples and the z-score formula for populations is that the z-score formula for populations uses  and  instead of x̄ and s.

List and describe the three types of distributions discussed in Chapter 4. If you were to randomly draw from each of these distributions, what values would you be most likely to draw?

If x = 55, and s = 3, when x = 50, z = -2.5.

Explain how and why you would convert a raw score to a z-score.

If you convert a distribution of scores to z-scores, the standard deviation of those z-scores will be equal to the standard deviation of the standard normal distribution.

If  = 2.5, and ^ = .25, when x = 4, z = 6.

What is the percentile rank of scores at z = -2.2 in normally distributed data?

74.86% of scores in a normal distribution fall below what z-score?

If x̄ = -1 and s² = 4, calculate x when z = 1.

The proportion of scores below z = .5 is .0000.

If z = -2, your raw score is located two standard deviations below the mean.

If  = 3 and  = 2, calculate z when x = 1.

In normally distributed data, what is the percentile rank of scores at z = 1.7?

A business owner is comparing sales between each of his three business locations for the month of July. He finds that sales from Store #3 had a z-score of 2.5. Which of these would accurately describe scores from Store #3?