Question 1

A scatterplot shows the value of 36 cars (in thousands of dollars) and their ages. The points trend downward as age increases. What is the best interpretation of this scatterplot?

Accepted Answer

The value of cars tends to decrease with age.

Question 2

A study finds a correlation coefficient of $$r = -0.98$$ between hours of exercise per week and resting heart rate. Which of the following is the best interpretation?

Accepted Answer

There is a strong negative linear association; more exercise per week is associated with a lower resting heart rate.

Question 3

Given the regression equation $$	ext{Calories} = 163.21 + 12.9 	imes 	ext{Total Fat}$$, what is the expected number of calories in an item with 23 grams of total fat?

Accepted Answer

$$860.91$$

Question 4

In the regression equation $$	ext{Calories} = 163.21 + 12.9 	imes 	ext{Total Fat}$$, what does the slope represent?

Accepted Answer

The number of calories per gram of total fat.

Question 5

Which of the following statements about the linear correlation coefficient $$r$$ are true?
I. If $$r = 0$$, there is no relationship between the variables.
II. If the slope of the regression line is positive, then $$r is $$negative.
III. The value of $$r is $$always between $$-1$$ and $$1.
IV$$. $$r = 0.45$$ suggests a stronger linear relationship than $$r = 0.22.$$

Accepted Answer

I, III, and IV only

Question 6

Suppose a regression equation is $$	ext{House Price} = 73.8 + 19.72 	imes 	ext{Number of Rooms}. $$What is the expected increase in house price for each additional room?

Accepted Answer

$$19.72$$ thousand dollars

Question 7

A survey finds a strong positive correlation between the percentage of a country's inhabitants that use cell phones and the life expectancy in that country. Which of the following best explains this result?

Accepted Answer

There is a lurking variable; richer countries have both higher cell phone use and better health care.

Question 8

If two events $$A$$ and $$B$$ are independent, what does that mean?

Accepted Answer

Knowledge that event $$A$$ occurred does not change the probability that event $$B$$ occurs.

Question 9

A person flips a coin two times. Using 'H' for heads and 'T' for tails, what is the sample space for the outcomes of this experiment?

Accepted Answer

$$\{HH, HT, TH, TT\}$$

Question 10

A probability experiment is conducted in which the sample space of the experiment is $$S = \{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12\}. $$Let event $$A = \{7, 8, 9\}. $$What is $$P(A) if $$each outcome is equally likely?

Accepted Answer

$$\frac{3}{12}$$

Question 11

In a large city, 61% of adults have health insurance. What is the probability that 2 adults selected randomly and independently both have health insurance? Round to two decimal places.

Accepted Answer

$$0.37$$

Question 12

Which of the following is an example of empirical probability?

Accepted Answer

Flipping a coin 50 times and recording the number of heads.

Question 13

Which of the following statements is true about the Law of Large Numbers (LLN)?

Accepted Answer

If an experiment is repeated a large number of times, the empirical probability will approach the theoretical probability.

Question 14

Suppose the regression equation for predicting BMI based on hours of video games played is $$	ext{BMI} = 19.947 + 0.5184 	imes 	ext{Games}. $$What is the expected BMI for a person who plays 10 hours of games per week?

Accepted Answer

$$25.131$$

Question 15

Which of the following values of the correlation coefficient is the strongest?

Accepted Answer

$$-0.85$$

Question 16

A probability experiment is conducted in which the sample space is $$S = \{1, 2, 3, 4, 5, 6, 7, 8, 9\}. $$Let event $$A = \{1, 2, 3\}$$ and event $$B = \{4, 5, 6, 7\}. $$What is $$P(A 	ext{ or } B)$$?

Accepted Answer

$$\frac{7}{9}$$

Question 17

Which of the following pairs of events are mutually exclusive?

Accepted Answer

The person was an Attorney and retired when he/she was between 56 and 60 years old.

Question 18

If the probability of event $$A is$$ $$0.6$$ and the probability of event $$B is$$ $$0.48$$, and the events are independent, what is the probability that both $$A$$ and $$B$$ occur?

Accepted Answer

$$0.288$$

Question 19

A probability experiment is conducted in which the sample space is $$S = \{A, B, C, D, E, F, G, H\}. $$Suppose the researcher randomly chooses a letter from $$S. $$What is the probability the letter is a vowel?

Accepted Answer

$$\frac{2}{8}$$

Statistics Study Guide: Correlation, Regression, Probability, and Data Interpretation

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