Normal Distributions and Data Analysis

Which statement best describes the relationship between the three types of distributions?

• They are completely independent of each other

• They serve identical purposes in statistics

• They build upon each other for statistical inference

• They cannot be used together

The distribution of assembly times required to assemble a certain smartphone is approximately normal with mean 4.6 minutes and standard deviation 0.6 minute. Of the following, which is closest to the percentage of assembly times between 4 minutes and 5 minutes?

• 34%

• 41%

• 59%

• 68%

• 95%

For a recent season in college football, the total number of rushing yards for that season is recorded for each running back. The mean number of rushing yards for the running backs that season is 790 yards. One running back had 1,637 rushing yards for the season, which is 2.42 standard deviations above the mean number of rushing yards. What is the standard deviation of the number of rushing yards for the running backs that season?

• 250 yards

• 300 yards

• 350 yards

• 400 yards

• 450 yards

The histogram shown summarizes the responses of 100 people when asked, “What was the price of the last meal you purchased?” Based on the histogram, which of the following could be the interquartile range of the prices?

• 40

• 21

• 10

• 5

• 3

Between what two standard deviations of a normal distribution contain 95% of the data?

• one below and one above

• two below and two above

• two below and zero

• zero and two above

This data is normally distributed.  What percentage of the data is in the shaded region?

• 68%

• 34%

• 17%

• 50%

What percent of a normal distribution lies outside of ±3 standard deviations?

• 99.7%

• .15%

• .3%

• 100%

What type of distribution is pictured?

• Right skewed

• Left skewed

• Random

• Normal

Question 28

• 1

• 2

• 3

• 4

This data is normally distributed.  What percent of the data is in the shaded region?

• 68%

• 95%

• 99.7%

• 50%