Probability Distributions

6.3 z-scores: The temperature is recorded at 60 airports in a region. The average temperature is 67 degrees Fahrenheit with a standard deviation of 5 degrees. Given a z-score of -0.2, what is the temperature? (Use formula, solve for x) 

• 65
• 68
• 67
• 66

6.3  Non-Standard Normal Distribution:  A bank's loan officer rates applicants for credit. The ratings are normally distributed with a mean of 200 and a standard deviation of 50. Find P60, the score which separates the lower 60% from the top 40%.

•  187.5
• 212.7
• 207.8
•  211.3

6.7 Binomial:  There is an 80% chance that an employer will check the educational background of a job applicant.  Sixty-four job applicants are randomly selected.  What is the probability that more than 50 applicants will have their background checked?

• 0.702
• 0.528
• 0.673
• 0.587

6.2:  Standard Normal Distribution (mean is 0 and standard deviation is 1).  Find the score that separates the lowest 98% from the highest 2%.

• - 2.05
• 2.05
• -1.95
• 1.95

6.2: Uniform distribution:  Suppose your phone battery can last anywhere between 2 hours and 8 hours depending on use. If the amount of time it lasts is distributed uniformly, what is the probability that the battery lasts less than 4 hours?

• 1/6
• 1/4
• 1/3
• 1/2

6.2:  Standard Normal Distribution (mean is 0 standard deviation is 1).  For a randomly selected subject, find the probability of a score between 1.37 and 2.42.

• 0.078
• 0.785
• 0.223
• 0.023

6.3:  Non-Standard Normal Distribution.  IQ scores are normally distributed with mean 100 and standard deviation 15.  Find the probability of randomly selecting an IQ score above 90.

• 0.683
• 0.748
• 0.715
• 0.796

6.3:  Non-Standard Normal Distribution.  IQ scores are normally distributed with a mean of 100 and standard deviation 15.  Find the IQ score separating the bottom 85% from the top 15%.

• 135
• 125
• 120
• 115

6.5 CLT:  Red blood cell counts of women are normally distributed with a mean of 4.577 and a standard deviation of 0.382.  Find the probability that one randomly selected woman has a red blood cell count above 5.4.

• 0.150
• 0.0156
• 0.215
• 0.0237

6.5 CLT:  Red blood cell counts of women are normally distributed with a mean of 4.577 and a standard deviation of 0.382.  What percentage of women have red blood cell counts in the normal range from 4.2 to 5.4?

• 82.3%
• 77.8%
• 72.6%
• 68%