Multiple choice questions

1) The extreme values of a data series affect :

a. The value of the median.

b. The value of the mean.

c. The value of the mean and the median.

d. The value of the first quartile.

e. None of the above.

2) We read on one of the websites that claims to explain basic statistics to non-regulars the following statements:

• A random variable never takes negative values.
• The variable "Employee registration number" is a quantitative variable measured on a nominal scale.
• In a hypothesis test, rejecting the null hypothesis H0 when in reality it is true represents type I error (or risk of the first kind).
• To decrease the margin of error of a confidence interval on an average, it is necessary to decrease the confidence level 1

Which of the above statements are TRUE?

a. Statement 1 and statement 2.

b. Statement 3 and statement 4.

c. Statement 2, statement 3, and statement 4.

d. All four statements.

e. None of the above.

3) We performed a linear regression analysis between the monthly turnover Y(in thousands of dollars) of a certain company and the monthly advertising costs X(in dollars). The empirical regression equation obtained is as follows: Y ^ = 120.12 + 4.12X.

Please complete the sentence: According to this equation, when you spend an additional $ 1 for a month on advertising, the monthly turnover of this business ...

Please choose an answer:

a. increases by $ 4.12.

b. increases by $ 124.24.

c. increases by $ 4,120.

d. increases by $ 4,240.12.

e. None of the above.

4) If X is a random variable that satisfies the following two equations:

{E [X] = 5E [X2] = 34

What is the coefficient of variation of X?

Please choose an answer:

a.30%.

b.40%.

c.60%.

d.80%.

e.None of the above.

5) Complete the following statement: "If there is a very strong correlation between two variables, then the correlation coefficient must be ..."

a. much greater than 1 if it is a positive correlation.

b. much less than 1 if it is a negative correlation.

c. much greater than 1 if it is a positive correlation, or much smaller than 1 if it is a negative correlation.

d. The statement cannot be completed since the mean value and the standard deviation value are missing.

e. None of the above.