The Normal Distribution

Which of the following histograms represents the data set given below?

Which of the following could best be represented using a continuous probability distribution?

The frequency for which different sized flat rate boxes are purchased at a post office.

The frequency of temperatures throughout the day in Florida on April 25th.

The frequency of different scores achieved on an Algebra test in a class of 30 students.

The number of students who use the internet for at least one hour after school.

Which of the following best describes the data given in the table below?

positively skewed

negatively skewed

normally distributed

none of the above

IQ scores are normally distributed with a mean of 100 and a standard deviation of 15. What percentage of people have an IQ between 130 and 100?

13.5%

47.5%

95%

27%

Which of the following best describes the probability distribution shown below?

positively skewed

negatively skewed

normally distributed

continuous probability distribution

The diagram below shows a normal distribution. 68% of the values fall within the shaded region, and x with bar on top is the mean. The scores in the shaded region range from 25 to 35. What is the mean of the values in the distribution?

5

10

30

60

The diagram below shows a normal distribution. 68% of the values fall within the shaded region, and is the mean. The scores in the shaded region range from 25 to 35. What is the standard deviation of the values in the distribution?

5

10

30

60

The number of home runs scored by teams in the Fayetteville baseball league are normally distributed and have a mean of 91 and a standard deviation of 12. What percentage of the teams have scored more than 115 home runs?

2%

13.5%

15.5%

98%

The number of hours that college freshman spend studying each week is normally distributed with a mean of 8 hours and a standard deviation of 5.5 hours. What percentage of students spend between 2.5 and 19 hours studying each week?

34%

68%

47.5%

81.5%