Free Practice Quiz Question List

5 Descriptive Statistics Online Quiz Questions

Use this free practice quiz with 20 questions to review 5 Descriptive Statistics, test your knowledge, and prepare for your next test or exam.

20 questions

True or false

1 point

The standard deviation describes spread in the same units as the original data.

A
True
B
False

True or false

1 point

A score at the 90th percentile means that the person answered 90% of the questions correctly.

A
True
B
False

Written response

1 point

A survey records 6 cats, 9 dogs, and 3 fish. Which category is the mode?

Fill in the blank

1 point

The range of a numerical data set is its maximum value minus its .

Fill in the blank

1 point

A numerical distribution with a longer tail toward larger values is .

Choose one

1 point

A shop records clothing sizes as small, medium, and large. How should this variable be classified?

A
Nominal categorical data
B
Ordinal categorical data
C
Numerical data
D
A numerical measurement with no categories

Choose one

1 point

Which graph most directly provides a compact display of a numerical data set's median, quartiles, and spread?

A
A bar chart
B
A box plot
C
A frequency table
D
A list of category labels

Choose all

1 point

Select all statements that correctly describe variance or standard deviation for numerical data.

A
The usual sample variance divides the sum of squared deviations by $n-1$ .
B
Sample variance is expressed in the same units as the original observations.
C
Sample variance uses squared deviations from the mean.
D
The standard deviation is the square root of the variance.

Choose all

1 point

When describing a numerical distribution, which features should you consider? Select all that apply.

A
Its center
B
Its spread
C
The order in which the observations were collected, regardless of relevance
D
Its shape and any unusual features

Choose one

1 point

For a data set with $Q_1=10$ and $Q_3=18$ , what is the common upper screening fence above which observations are flagged as potential outliers?

A
18
B
26
C
30
D
42

Written response

1 point

Find the median of the ordered values $2, 4, 8, 10$ . Enter a numerical value.

Choose one

1 point

A researcher records eye color, a nominal categorical variable. Which graph is an appropriate way to compare how many observations fall in each category?

A
A bar chart
B
A histogram
C
A box plot
D
A line graph

Choose one

1 point

In a survey of $30$ people, $12$ report taking the bus. What is the bus category's relative frequency as a percentage?

A
$12\%$
B
$40\%$
C
$60\%$
D
$250\%$

True or false

1 point

The 50th percentile of ordered numerical data is the median. True or false?

A
True
B
False

Choose one

1 point

What is a histogram especially useful for when summarizing numerical data?

A
To see the overall shape of a numerical distribution
B
To display the names of nominal categories in natural order
C
To show the exact value of every observation
D
To summarize only the median and quartiles

Choose one

1 point

A survey records responses as small, medium, or large. Which approach best summarizes this ordinal variable?

A
Arrange the categories alphabetically and calculate their mean
B
Treat the category labels as numerical intervals and make a histogram
C
Discard the order and report only the largest category's count
D
Preserve the categories' natural order and, when useful, report cumulative frequencies

Written response

1 point

What is the name of the measure defined by $Q_3-Q_1$ ?

Choose one

1 point

A numerical distribution is strongly right-skewed and includes an unusually large observation. Which pair of measures is usually the more representative summary of its center and spread?

A
Mean and standard deviation
B
Median and interquartile range
C
Mode and range
D
Mean and range

Written response

1 point

For the data $2, 4, 6$ , calculate the sample variance using the usual sample formula. Enter the exact numerical value.

Open ended

1 point

A researcher records eye color as blue, brown, or green, and assigns the codes $1$ , $2$ , and $3$ to those categories. The researcher proposes reporting the mean code. Explain why that mean is not meaningful and recommend a suitable summary of the data.