# chapter 10 Flashcards

- Assuming there is a statistical relationship between height and weight for adult females, which of the following statements is true?

a. If we knew a woman’s height, we could predict her weight.

b. If we knew a woman’s height, we could determine the exact weight for all women with that same height.

c. If we knew a woman’s height, we could predict the average weight for all women with that same height.

d. All of the above are true.

C

- Statistical relationships such as correlation are useful for describing features of __________.

a. An individual from the population.

b. A sample from the population.

c. An aggregate or population.

d. All of the above.

C

- Most researchers are willing to declare that a relationship is statistically significant if the chances of observing the relationship in the sample when actually nothing is going in the population are less than what percent?

a. 5%

b. 50%

c. 95%

d. None of the above

A

- A relationship is considered to be statistically significant if that relationship is stronger than what percent of the relationships we would expect to see just by chance?

a. 5%

b. 95%

c. 50%

d. None of the above

B

- Which of the following statements is true?

a. If a relationship is found to be statistically significant, there is a strong relationship between the two measurement variables.

b. A relationship that is not found to be strong can still be statistically significant.

c. If researchers fail to find a statistically significant relationship, then no relationship exists between the two measurement variables.

d. None of the above statements are true.

B

- Which of the following is true if a relationship is found to be statistically significant?

a. Researchers have declared that the relationship found in the sample is not a fluke.

b. The chances of observing the relationship in the sample when nothing is actually going on in the population are small (less than 5%).

c. This relationship is stronger than 95% of the relationships we would expect to see just by chance.

d. All of the above.

D

- Which of the following describes a strong statistical correlation?

a. The value of one measurement variable is always equal to the square of the value of another measurement variable.

b. One measurement variable has a cause and effect relationship with another measurement variable.

c. Two measurement variables have a strong linear relationship.

d. All of the above.

C

- Suppose the correlation between two measurement variables is −1. Which of the following statements is not true?

a. As one of the variables increases, the other decreases.

b. The data looks the same as when two variables have a deterministic linear relationship.

c. The correlation between the variables is very weak.

d. All of the above statements are true.

C

- Which of the following is a correct interpretation of a correlation?

a. “The correlation is −.85. This means students with lower verbal SAT scores tend to have lower GPAs as well.”

b. “The correlation between husbands’ and wives’ ages is −.85, so the correlation between wives’ and husbands’ ages is +.85.”

c. “The correlation is −.85. This means that as the distance of a golf putt goes up, the success rate of making the putt goes down..”

d. All of the above.

C

- {Study time and exam score narrative} For which values of study time does the professor’s regression equation make sense in terms of predicting exam scores?

a. Between 0 and 20 hours.

b. Between 0 and 100 hours.

c. Anything greater than or equal to 0 hours.

d. It is not possible to predict exam score with study time.

A

- {Study time and exam score narrative} Suppose the professor later found out that his correlation was not +.80, but rather it was +.08. How does this change the predictions he can make about exam scores based on study time?

a. You have to take the results and divide them by 10, because .80/10 = .08.

b. It won’t change the predictions because the regression line stays the same.

c. The predictions should no longer be used because they won’t be very accurate.

d. Not enough information to tell.

C

- What type of statistical error is being made in the following statement? “If this uphill linear trend continues, 50 years from now, one out of every three of us will be an Elvis impersonator.”

a. Extrapolation

b. Exaggeration

c. Overprediction

d. Expectation

A

- Which of the following describes a ‘detrended’ time series?

a. It has a decreasing long-term trend in it.

b. It randomly fluctuates, sometimes with an increasing trend and sometimes with a decreasing trend.

c. It has a long-term trend that was removed in order to look for other interesting features.

d. All of the above.

C

- {Crickets and temperature narrative} For about what range of cricket chirps can the researcher feel comfortable about making temperature predictions?

a. 15-40 chirps per 15 seconds

b. 60-80 degrees

c. 0-40 chirps per 15 seconds

d. Any range is acceptable.

A