STAT 121 Exam 1 Review

A factory supervisor selects 40 employees at random to conduct a work satisfaction survey. What is the population in this study?

• All employees at the company

• The 40 randomly selected employees

• The factory supervisor

• All satisfied employees at the company

Temperatures follow a normal distribution with 2.5% of values less than 10° and 2.5% of values above 100°. What is the standard deviation of temperatures?

• 55 degrees

• 22.5 degrees

• 10 degrees

• 95%

The time it takes for college freshman to complete the Mason Basic Reasoning Test is normally distributed with a mean of 24 minutes and a standard deviation of 5 minutes. What is the range for the middle 99.7% of the time for the Reasoning Test completion of college freshman?

• 15

• 20

• 30

• 35

Scores on a standard aptitude test are approximately normally distributed with a mean of 100 and a standard deviation 10. What percent of scores are between 80 and 110?

• 81.5%

• 50%

• 95%

• 68%

Which of the following is a false statement about the standard deviation s?

• s can be less than zero

• s is measured in the units of the response variable

• s would increase if we added an unusually high observation

• if s is small, this suggests the data is clustered towards the mean

Given the 5 number summary 2,3,5,15,40, what is the shape of this data?

• left skewed

• right skewed

• bell shaped

• bimodal

What is the shape of the data this boxplot represents?

• We can't tell the shape of data by looking at a boxplot

• symmetric

• right skewed

• left skewed

Birth weights follow a normal distribution. A hospital administrator wants to assess the distribution of birth weights at the hospital where she works. Which of the following intervals will include the smallest

proportion of birth weights?

• Median to Maximum

• Minimum to Q3

• (Mean – 2SD) to Q3

• (Mean – 1SD) to (Mean + 1SD)

The number of rushing yards by a college football team in each of 8

games is given below:

400 400 410 50 350 400 350 200

Calculate the measure of center which best summarizes the number of yards passing by

the team.

• 375

• 400

• 320

• 350

A manufacturing process produces bags of cookies that have Normally distributed weights with a mean of μ = 15.0 oz. and a standard deviation of σ = 0.4 oz. What is the probability that a randomly selected bag weighs more than 15.2 oz?

• 0.0228

• 0.9772

• 0.3085

• 0.6915