# A tire shop has 200 tires in stock. Assume that 15 of these tires are defective. You randomly choose 3 tires. What is the probability that you choose 3 tires that are not defective? (Round your answer to 3 decimal places)

**Question 1** (Mandatory) (0.25 points)

Which of the graphs represents the strongest correlation?

Question 1 options:

First | |

Second | |

Third |

**Question 2** (Mandatory) (0.25 points)

Which of the following scatterplots have a correlation coefficient close to r = 0.85?

Question 2 options:

First | |

Second | |

Third |

**Question 3** (Mandatory) (0.25 points)

A study compared the body weight (in Kg) and the brain weight (in grams) for a sample of 20 mammals. It was determined that the linear correlation coefficient is 0.0099. What is the value of the correlation coefficient indicating?

Question 3 options:

Brain weight and body weight are positively correlated. As body weight increases, brain weight is also increasing. | |

Brain weight and body weight are negatively correlated. As body weight increases, brain weight is decreasing. | |

Brain weight and body weight are not correlated. As body weight increases, brain weight tends to remain the same. | |

Brain weight and body weight are positively correlated. As body weight increases, brain weight is decreasing |

**Question 4** (Mandatory) (0.25 points)

A local business owner wants to know if there is an relationship between the high temperature of the day (°F) and their daily hot coffee sales ($). What is the response variable in this situation.

Question 4 options:

Location of the coffee shop | |

Daily hot coffee sales | |

High temperature of the day | |

Hours of operation |

**Question 5** (Mandatory) (0.25 points)

A local business owner wants to know if there is an relationship between the high temperature of the day (°F) and their daily hot coffee sales ($). What is the explanatory variable in this situation.

Question 5 options:

Location of the coffee shop | |

Daily hot coffee sales | |

High temperature of the day | |

Hours of operation |

**Question 6** (Mandatory) (0.25 points)

The table below shows the midterm exam score and the overall grade for a random sample of 12 students in a statistics course. Calculate the value of the correlation coefficient *r* between midterm exam scores and overall grades. Give the answer with two decimal places. Click here to open the data in StatCrunch.

Question 6 options:

**Question 7** (Mandatory) (0.5 points)

Question 7 options:

The regression equation for predicting number of speeding tickets (Y) from information about driver age (X) is

The slope =

The y-intercept =

**Question 8** (Mandatory) (0.25 points)

Before buying a new car, a consumer wants to learn how the weight of a car affects highway gas mileage. Statistical software was used to conduct a simple linear regression about the relationship between the weight (in lbs) of a car and its highway mpg. The following equation for the regression line was given:

If your car weighs 3200 lbs, what does the model predict the highway mpg? *Round to 1 decimal places.*

Question 8 options:

**Question 9** (Mandatory) (0.25 points)

The table shows the number of hours a student studied during a week for an exam and the grade received on the exam. Find the regression equation.

Click here to open this data in StatCrunch.

Question 9 options:

**Question 10** (Mandatory) (0.25 points)

Research shows that infant mortality rate (number of infants less than a year old who die per every 1,000 live births) is a strong predictor of average life expectancy. The regression equation gives a y-intercept of 70 and a slope of – 0.05.

Given the information above, which of the following equations correctly represents the relationship between infant mortality rate (IMR) and average life expectancy (ALE)?

Question 10 options:

**Question 11** (Mandatory) (0.25 points)

The following is the linear regression equation for the price of diamonds of different sizes (carat) US dollars in 2004.

Write a sentence that accurately interprets the slope.

Question 11 options:

**Question 12** (Mandatory) (0.75 points)

Question 12 options:

The data below displays the number of text messages that a person sends daily and their age. Click here to open the data in StatCrunch.

What is the **observed** number of texts that a 30 year old sent daily?

In your linear regression equation, round your slope and y-intercept to 1 decimal place. What does the regression equation **predict** the** **number of texts that a 30 year old would send daily to be?

What is the residual for a 30 year old?

**Question 13** (Mandatory) (0.25 points)

A study of class attendance and grades among first-year students at a college showed that, in general, students that attended a higher percent of their classes earned higher grades. Class attendance explained 18% of the variation in grade index among the students. What is the numerical value of the correlation *r* between percent of classes attended and grade index?

Question 13 options:

r = – 0.424 | |

r = 0.424 | |

r = 1.80 | |

r = 0.032 |

**Question 14** (Mandatory) (0.25 points)

The method of least squares picks the slope and intercept of the sample regression equation by minimizing the sum of squared residuals

Question 14 options:

True | |

False |

**Question 15** (Mandatory) (0.25 points)

Data has been collected for a random sample for the daily temperature and the amount of money from ice cream sales. The temperatures ranged from 60° to 95°. The least squares regression line is computed. Which statement best describes using the line to predict sales when the temperature is 47°?

Question 15 options:

The prediction may be helpful but is less reliable because the value is much lower than the data range. | |

The prediction is reliable because regression is used. | |

It will not be possible to compute the sales number. |

## M2:L1 and M2:L2

Questions from Homework 4 in 14 week course

**Question 16** (Mandatory) (0.5 points)

Question 16 options:

You select a name at random from a hat that contains 33 freshmen, 34 sophomores, 30 juniors, and 28 seniors.

What are the total number of possibilities?

Suppose you want to select a senior’s name. How many possibilities is this?

**Question 17** (Mandatory) (0.25 points)

You select a name at random from a hat that contains 33 freshmen, 34 sophomores, 30 juniors, and 28 seniors. What is the probability that the name is a senior’s?

Question 17 options:

**Question 18** (Mandatory) (0.25 points)

You will select one card from a standard deck of 52 cards. What is the probability that you select a red queen?

Question 18 options:

0.154 | |

0.077 | |

0.038 | |

0.962 |

**Question 19** (Mandatory) (0.25 points)

The last 1500 Air America flights 315 have been delayed. What is the probability that a flight with this airline will **not** be delayed?

Question 19 options:

**Question 20** (Mandatory) (0.25 points)

The table below shows the class of ticket and whether a person survived the *Titanic*:

If a passenger is randomly chosen what is the probability they were a first or second class ticket holder? (*Round your answer to 3 decimal places)*

Question 20 options:

**Question 21** (Mandatory) (0.25 points)

The table below shows the class of ticket and whether a person survived the *Titanic*:

If a passenger is randomly chosen what is the probability they were a crew member or did not survive? (*Round your answer to 3 decimal places)*

Question 21 options:

**Question 22** (Mandatory) (0.25 points)

The table below represents the blood type and gender of 250 U.S citizens. If a person is randomly selected, what is the probability that they their blood type is type A or type O?

Question 22 options:

**Question 23** (Mandatory) (0.25 points)

The table below represents the blood type and gender of 250 U.S citizens. If a person is randomly selected, what is the probability that they their blood type is type B or male?

Question 23 options:

0.52 | |

0.056 | |

0.476 | |

0.576 |

**Question 24** (Mandatory) (0.25 points)

An office building has 2 fire detectors. Suppose that 3 out of every 100 fire detectors will fail to go off during a fire. Find the probability that both of these fire detectors will fail to go off during a fire. *Assume that these two fire detectors are independent of each other. *

Question 24 options:

0.06 | |

0.09 | |

0.0009 | |

0.94 |

**Question 25** (Mandatory) (0.5 points)

Two machines are selected at random without replacement from 10 for inspection. Suppose that unknown to the inspector, three of the ten machines are defective. Find the probability that both machines picked for inspection are defective?

Question 25 options:

0.6 | |

0.522 | |

0.067 | |

0.1 |

**Question 26** (Mandatory) (0.5 points)

Question 26 options:

According to the National Health and Nutrition Examination Survey (1999-2008), 35.7% of U.S. adults were considered obese (BMI ≥ 30). You randomly select two people in the U.S. and calculate their BMI.

Are these two events independent?

What is the probability that both are obese?

*Round your answer to 3 decimal places.*

**Question 27** (Mandatory) (0.5 points)

A tire shop has 200 tires in stock. Assume that 15 of these tires are defective. You randomly choose 3 tires. What is the probability that you choose 3 tires that are not defective? (*Round your answer to 3 decimal places)*

Question 27 options: