# Chapter 4: Central Tendency And Variability

25 Questions | Total Attempts: 2082  Settings  Central Tendency Measures of Variability

• 1.
The symbol represents:
• A.

An individual score.

• B.

The mean of a sample of scores.

• C.

The sum of a sample of scores.

• D.

The total number of scores.

• 2.
If our data is nominal we should use _________ as a measure of central tendency.
• A.

Mean

• B.

Mode

• C.

Median

• D.

Standard deviation

• 3.
The Lee family is looking to buy a house in one of two suburban areas just outside of a major city, and the air quality is a top priority for them. One suburb advertises the use of hybrid cars and solar panels, while the other area focuses on its convenient bus routes and availability of Hummer dealerships. Is the mean or median the better measure to use for deciding which area has better air quality? (Hint: these populations are skewed.)
• A.

The median, because it is not affected by outliers.

• B.

The median, because it is less biased by skewness being dependent on the middle score.

• C.

The mean, because it is always the best measure of central tendency in any population.

• D.

The mean, because it represents the balance of the distribution.

• 4.
The simplest (and least useful) measure of variability is the:
• A.

Range.

• B.

Mode.

• C.

Variance.

• D.

Standard deviation.

• 5.
The standard deviation of a population is symbolized by:
• A.

SD

• B.

S

• C.

σ

• D.

SS

• 6.
The symbol SS stands for:
• A.

Sample standard deviation.

• B.

Sigma squared.

• C.

Sum of squared deviations.

• D.

Sum of squared scores

• 7.
Outliers have the greatest effect on the:
• A.

Mean.

• B.

Median.

• C.

Percentile.

• D.

Mode.

• 8.
A graduate statistics class is unhappy with midterm grades. The professor will curve the grades only if the class figures out how much the curve needs to be for the mean score to equal 85. What should the curve for the class be if these are the midterm scores for class members: 72, 88, 95, 76, 69, 71, 81, 80, 73, and 85.
• A.

12 points

• B.

2 points

• C.

9 points

• D.

6 points

• 9.
The standard deviation (SD) is most commonly used to get a sense of how far the typical score of a distribution differs from the mean. In computing the SD, why is it necessary to square the deviations from the mean for each score?
• A.

The deviations are too small to have a variance without being squared.

• B.

There is no variability in the deviations of the scores prior to squaring.

• C.

The mean of the deviations balances out to zero due to negative and positive values.

• D.

Squaring numbers is fun.

• 10.
__________ is the square root of the average of the squared deviations from the mean.
• A.

Variance

• B.

Range

• C.

Standard deviation

• D.

Sum of squares

• 11.
It is possible that a distribution of scores could have more than one:
• A.

Mode.

• B.

Median.

• C.

Standard deviation.

• D.

Mean.

• 12.
Which of the following refers to a single score in a distribution of scores?
• A.

N

• B.

Σ

• C.

X

• D.

μ

• 13.
Because it uses every score in a distribution and is easy to interpret, the ___________ is the most common measure of variability.
• A.

Variance

• B.

Mean

• C.

Range

• D.

Standard deviation

• 14.
Rasheed examined the GRE math scores of the first-year graduate students in his statistics class to see the variability. Rasheed found the variance to be 1440. What is the standard deviation?
• A.

120

• B.

1440

• C.

2,073,600

• D.

570

• 15.
Numbers based on samples are referred to as ______________ while numbers based on populations are referred to as _______________.
• A.

Statistics; parameters

• B.

Parameters; statistics

• C.

Descriptive statistics; inferential statistics

• D.

Central tendency; variability

• 16.
In a journal article, the standard deviation would be symbolized as:
• A.

Sd

• B.

S

• C.

SS

• D.

SD

• 17.
Mark decides to use the mode as the measure of central tendency for his map study. What is the mode in his data set: 3, 17, 22, 5, 4, 16, 27, 22, 17, 22, 5, and 3?
• A.

27

• B.

17

• C.

5

• D.

22

• 18.
A parameter is:
• A.

A measurement based on a sample of scores.

• B.

A measure of variability.

• C.

A measurement based on a population of scores.

• D.

A measure of central tendency.

• 19.
If you calculate the standard deviation of a distribution of scores and obtain a value of 0, which of the following statements is true?
• A.

The sample size is very small.

• B.

You made an error in your calculations - it isn't possible to obtain a standard deviation of 0.

• C.

The range will also be 0.

• D.

There is no variability in the distribution - that is, all of the scores are the same.

• 20.
For the scores, 7, 5, 4, 6, 7, 8, the median would be:
• A.

6.17

• B.

6.5

• C.

7

• D.

5

• 21.
In computing variance and standard deviation we are interested in how much individual scores vary from:
• A.

N.

• B.

What we would expect by chance.

• C.

The highest score in the distribution.

• D.

The mean.

• 22.
A researcher is interested in the amount of time students spend on social networking sites. She obtains a sample of 10 students and records the amount of time (in minutes), in one day, they spend on Facebook, MySpace, or Twitter. Assume that the following summary information is from her data: N = 10, μ = 47.7, SS = 2000. What is the standard deviation for this example?
• A.

20000

• B.

4.77

• C.

14.14

• D.

200

• 23.
Obtaining a measure of intelligence from a group of college students would likely yield a somewhat normal distribution (that is, there shouldn't be any extreme outliers). What would be the best measure of central tendency to use in this example?
• A.

Median.

• B.

Any of the three measures of central tendenc

• C.

Mean

• D.

Mode

• 24.
The dean of a local college needs to drop one course from the art program. She decides to pick the course with the lowest average enrollment rate from the previous four semesters. The enrollments of three courses she is considering are: Photography: 30, 20, 12, 22; Film Editing: 11, 29, 27, 29; Abstract Art: 18, 22, 21, 24. Which class has the lowest mean enrollment over the past 4 semesters?
• A.

All three classes have the same mean.

• B.

Photography

• C.

Film editing

• D.

Abstract art

• 25.
To compute the variance, the sum of the squared deviations is divided by:
• A.

N.

• B.

X.

• C.

The mean.

• D.

SS.

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