Statistical Distributions

A pizza company is interested in the average number of pizzas eaten each year by people. They send out 30 volunteers to conduct research by collecting random samples of 25 people each and determine the number of pizzas that the people in the group ate in the previous year. After looking at the sample means, the company sees that the distribution is approximately normal, with a mean of 6.4 pizzas eaten and a standard deviation of 0.6 pizzas.

What interval is likely to contain the true mean number of pizzas eaten in the previous year by the population?

Based the normal curve on the previous slide, estimate the proportion of people who ate less than 6.4 pizzas last year.

Based the normal curve on the previous slide, estimate the proportion of people who ate more than 7 pizzas last year.

ANOVA tests use which of the following distributions?

• F

• t

• Z

• Chi-square

Which of the distributions displayed in the dot plots below has the highest standard deviation?

• Distribution A

• Distribution B

• Distribution C

The distances male long jumpers for State College jump are approximately normal with a mean of 263 inches and a standard deviation of 14 inches.  
What is the probability the next male long jumper from State College jumps longer than 270 inches?

• 0.1888

• 0.3085

• 0.8035

• 0.3585

According to the portion of the frequency table given, how many people have an MBA?

• 9

• 20

• 60

• not enough information

The mean weight of an adult female beagle is 28 pounds with a standard deviation of 3 pounds.  The mean weight of an adult female boxer is 70 pounds with a standard deviation of 6 pounds.  A beagle named Suzie weighs 34 pounds.  How much would a female boxer have to weigh in order for her to have the same z-score as Suzie?

• 70 pounds

• 76 pounds

• 80 pounds

• 82 pounds

Here is the dot plot of voter turnout (as a percentage of voting-age population) for the 50 states—plus the District of Columbia—in a recent presidential election. Which of the following best describes this distribution?

• The distribution of voter turnout is skewed slightly left, centered at about 62%, with a range of 24%.

• The distribution of voter turnout is roughly symmetric, centered at about 60%, with a range of 30%.

• The distribution of voter turnout is skewed slightly right, centered at about 62%, with a range of 24%.

• The distribution of voter turnout is bimodal, centered at about 60%, with a range of 30%.

According to the 1.5 x IQR rule, how many outliers are there in the data set 72, 110, 114, 115, 118, 123, 144, 156?

• None

• One

• Two

• Three