Q: Coal is processed at The University of Georgia. The percentage of ash in coal particles is related to density. Using the regression equation $$y = 4.88 + 0.525x$$, what is the predicted percentage of ash for a coal particle with density 1.35 g/cc?

$$y = 4.88 + 0.525 \times 1.35 = 5.59$$

Question 1

Planning the methods for data collection to study the effects of Vitamin E on athletic strength would be classified as which aspect of statistics?

Accepted Answer

Description

Question 2

A statistics teacher records each student’s major, gender, and age. The variable 'major' is an example of which type of variable?

Accepted Answer

Categorical

Question 3

A stock broker tracks whether various stock values are up, unchanged, or down at the end of the month. What is the variable of interest?

Accepted Answer

Stock performance (up, same, down)

Question 4

Is the stock performance variable (up, same, down) categorical or quantitative?

Accepted Answer

Categorical

Question 5

A sporting goods retailer surveyed customers about their primary reason for shopping at their store. If 40 out of 100 customers said 'merchandise', what is the proportion?

Accepted Answer

$$ \frac{40}{100} = 0.40 $$

Question 6

Which of the following best describes nonresponse bias?

Accepted Answer

It occurs when the subject does not respond to the survey.

Question 7

In a clinical trial, why should participants be randomly assigned to treatment groups?

Accepted Answer

To minimize the effects of confounding variables

Question 8

Given the stem-and-leaf plot below, what is the mode rating?
Stem | Leaf
4 | 5 5 6 7 8 9
5 | 0 1 2 2 3 4 5 6 7 8 9
6 | 0 1 2 3 4 5 6 7 8 9
7 | 0 1 2 3 4 5 6 7 8 9

Accepted Answer

6

Question 9

Which statement is true about residuals in a scatterplot?

Accepted Answer

The residual for an observation is the vertical distance between the point and the regression line.

Question 10

For the 14 teams in baseball’s American League, the correlation with number of wins in the 2007 regular season is 0.51 for shutouts, 0.61 for hits made, -0.70 for runs allowed, and -0.56 for homeruns allowed. Which variable has the strongest linear association with number of wins?

Accepted Answer

Runs allowed

Question 11

Choose the statement that best states the meaning of the slope in this context: 'A slope tells us that a one degree increase in temperature is associated with an average increase in ticket sales of 125.'

Accepted Answer

The slope tells us that high temperatures are causing more people to buy tickets to the water park.

Question 12

Given the data: $$x = 0, 3, 4, 5, 12$$ and $$y = 8, 6, 9, 12, 12$$, which regression equation best fits the data?

Accepted Answer

$$y = 4.88 + 0.525x$$

Question 13

Coal is processed at The University of Georgia. The percentage of ash in coal particles is related to density. Using the regression equation $$y = 4.88 + 0.525x$$, what is the predicted percentage of ash for a coal particle with density 1.35 g/cc?

Accepted Answer

$$y = 4.88 + 0.525 	imes 1.35 = 5.59$$

Question 14

Which of the following is an example of a quantitative variable?

Accepted Answer

Number of siblings

Question 15

Which of the following is a method to minimize bias in a survey?

Accepted Answer

Randomly select participants

Question 16

If $$r = -0.70$$ for the correlation between runs allowed and number of wins, what does this indicate?

Accepted Answer

As runs allowed increases, number of wins tends to decrease.

Question 17

A researcher wants to study the effect of a new drug on blood pressure. Which aspect of statistics is being used when the researcher analyzes the results?

Accepted Answer

Inference

Question 18

Which of the following is NOT a reason to use random assignment in experiments?

Accepted Answer

To ensure all groups receive the same treatment

Question 19

In a frequency table, what does the relative frequency represent?

Accepted Answer

The proportion of occurrences out of the total

Statistics Study Guide: Data Types, Bias, Regression, and Data Analysis

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