What is the biggest disadvantage of summarizing the dispersion of a dataset with the variance?

Question 1 options:

The variance is sometimes twice the range.

The variance is always twice the range.

The units are in the original form.

The units are squared.

The value cannot be negative.

The value always contains outliers.

None of these

Under which of the following circumstances would a sample variance be zero?

Question 2 options:

If the mean was zero

If the mean, median and mode were the same number

Variance can never be zero

None of these

If exactly half of the values were above the mean and half below the mean

If all the values in the sample were the same

If the variance of a dataset is correctly computed with the formula using (n – 1) in the denominator, which of the following is true?

Question 3 options:

The degrees of freedom will be twice the standard error.

None of these

The variance will be negative.

The dataset is a sample.

The variance will be zero.

The variance is a population parameter.

Which of the following measures of central tendency will always change if a single value in the data changes?

Question 4 options:

None of these

Mode

Mean

Midrange

Variance

Standard deviation

Median

If a positively skewed distribution (right skewed) has a median of 50, which of the following statement is true?

Question 5 options:

None of these

The mean and median are the same

The mode and the median are the same

The variance is negative

The mean is less than 50

The mode is greater than 50

Which of the following variables are not of the ratio level of measurement?

Question 6 options:

Length

None of these

Loudness

Luminosity

Temperature (in Celsius)

Time (in seconds)

Velocity

A grocery store is interested in knowing how many times a typical customer visits in a week.  They decide to randomly pick a customer passing through the front door and ask every tenth customer on a specified day to complete a short survey including information about how many times they have visited the store in the past week.  What kind of a sampling design is this?

Question 7 options:

None of these

Stratified

Convenience

Multistage

Simple random

Cluster

Suppose that the following tree diagram depicted the results of a survey about the choice of condiment sauces.  Based on this diagram, is the probability that a respondent would choose a particular sauce independent of the type of meat?  Why or why not?

Tree Diagram

Question 8 options:

They are not independent, because the same sauce is used regardless of the type of meat.

They are independent, because the same sauce is used regardless of the type of meat.

They are not independent, because the sauces have the same probability of being chosen.

They are not independent, because the probability of a sauce is related to the type of meat.

They are independent, because the probabilities are the same regardless of the type of meat.

They are independent, because the sauces have the same probability of being chosen.

Suppose a school sports team has 12 players, of which 10 are taking at least one foreign language class.  The school offers only Spanish and French classes.  If 8 of the players are taking Spanish and 5 of the players are taking both languages, what is the probability that a random chosen 

player from this team is taking French?

Question 9 options:

3/12

10/24

10/12

None of these

7/24

3/10

7/12

What is the probability that, of three randomly selected people, none were born on Monday?

Question 10 options:

1/343

1400/2401

342/343

1/2401

None of these

2400/2401

240/343

Consider the following contingency table for a drug test.

What is the sensitivity of this test?

Question 11 options:

1/5a

2a

75%

3a

None of these

60%

67%

40%

Consider the following contingency table for a drug test.

Which of the following has the highest value?

Question 12 options:

Sensitivity and specificity

Positive predictive value

Negative predictive value and specificity

Positive predictive value and sensitivity

Specificity

Sensitivity

Negative predictive value

None of these

Positive predictive value and specificity

Bag A contains 5 blue marbles and 3 red marbles.  Bag 2 contains 4 blue marbles and 6 red marbles.  If a bag is selected at random and a ball is drawn from it, what is the probability that the marble is not blue?

Question 13 options:

3/16

6/20

39/40

9/40

124/320

None of these

156/320

Consider the following set of numbers a population.

     3     3     5     6     7     12

What is the variance?

Question 14 options:

56/6

56/5

65/6

38/5

None of these

56/5

38/6

For the data depicted in the boxplot below, what is the upper bound for check for outliers?

Question 15 options:

105

97

90

110

None of these

100

95

In the data set below, which of the values are outliers using the Quartile Method?

4, 13, 27, -10, 6, 5, 8, -15, 8, 15, 28, 2

Question 16 options:

-15 and -10

-15, -10 and 28

-15

28

There are no outliers in this data set.

-15 and 28

-15, 27 and 28

27 and 28

Suppose a lie detector machine has an 8% False Negative rate.  A group of 100 subjects are asked a sensitive question and one quarter of the subjects decide to lie.  From this group, the machine has 75 positive results.  What is the specificity of this test?

Question 17 options:

None of these

58.25%

30.67%

45.05%

85.25%

25.25%

39.98%