Free Practice Quiz Question List

02 Descriptive Statistics Online Quiz Questions

Use this free practice quiz with 20 questions to review 02 Descriptive Statistics, test your knowledge, and prepare for your next test or exam.

20 questions

Choose one

1 point

A school surveys students about their preferred transportation method. Which display is most appropriate for comparing the responses?

A
A bar graph of students' preferred transportation methods
B
A histogram of students' preferred transportation methods
C
A line graph of students' preferred transportation methods over categories
D
A scatterplot of students' preferred transportation methods against category labels

Choose one

1 point

Why do the bars in a histogram normally touch, whereas the bars in a bar graph are separated?

A
The categories have been ranked from smallest to largest
B
The graph compares two categorical variables
C
Adjacent intervals represent a numerical continuum
D
The observations in each interval are all identical

Choose one

1 point

A real-estate dataset is strongly right-skewed because a few luxury homes have exceptionally high prices. Which measure of center is generally most appropriate for describing a typical home price?

A
Median, because it is resistant to extreme values
B
Mean, because it uses every observation and is never affected by extremes
C
Mode, because it always represents the center of a quantitative distribution
D
Range, because it gives the typical home price

True or false

1 point

True or false: Standard deviation is expressed in the same units as the original observations.

A
True
B
False

True or false

1 point

True or false: When an observation is identified as a potential outlier, it should be investigated rather than automatically deleted.

A
True
B
False

Fill in the blank

1 point

Complete the definition: Relative frequency equals .

Fill in the blank

1 point

Complete the definition: Cumulative frequency is the of observations at or below a specified value.

Open ended

1 point

Describe a practical workflow for analyzing a new quantitative dataset. Explain how you would choose numerical summaries when the distribution is roughly symmetric versus skewed or affected by extreme values.

Choose all

1 point

Select all statements that correctly compare the mean and median.

A
The mean uses every observation.
B
The median is always larger than the mean in a right-skewed distribution.
C
The median is generally more resistant to extreme values than the mean.
D
The mean and median are both calculated from only the minimum and maximum.

Choose one

1 point

A survey records each student's favorite book genre. Which display is most appropriate for comparing the numbers of students in the different genres?

A
A histogram, because favorite genre is quantitative
B
A bar graph, because favorite genre consists of categories
C
A line graph, because every student gives one response
D
A scatterplot, because the responses can be paired

Written response

1 point

In the frequency distribution for books read, 6 of the 20 students read exactly 2 books. What is the relative frequency for 2 books?

Choose one

1 point

A frequency distribution has frequencies 3, 5, 6, and 4 for values 0, 1, 2, and 3, respectively. What is the cumulative frequency at or below 2?

A
6
B
8
C
14
D
20

Choose one

1 point

Home prices in a neighborhood are strongly right-skewed because a few luxury homes are much more expensive than the rest. Which measure of center is generally most appropriate for describing a typical home price?

A
The mean, because it uses every observation and is sensitive to extreme values
B
The median, because it is resistant to extreme values
C
The mode, because every home price is a category
D
The range, because it measures the typical value

Written response

1 point

A test score is 85, the sample mean is 70, and the sample standard deviation is 10. Using $z=\frac{x-\bar{x}}{s}$ , what is the student's z-score?

Choose one

1 point

Why does the sample variance formula divide by $n-1$ rather than by $n$ ?

A
The sample contains only categorical observations
B
Subtracting 1 removes the effect of the sample mean
C
The sample variance measures the median rather than the mean
D
The denominator $n-1$ accounts for estimating population variation from a sample

Choose one

1 point

A data set has $Q_1=10$ and $Q_3=18$ . According to the 1.5-IQR rule, what is the upper fence for potential outliers?

A
20
B
26
C
30
D
42

True or false

1 point

True or false: Converting scores from two variables to z-scores can support comparison even when the variables use different measurement units.

A
True
B
False

Choose all

1 point

A researcher is grouping quantitative observations into class intervals. Select all requirements that make the intervals appropriate for a frequency distribution.

A
Class intervals should not overlap.
B
Class intervals should cover all relevant observations.
C
Class intervals must represent separate categories rather than numerical ranges.
D
Class intervals should generally have equal widths unless there is a clear reason to use unequal widths.
E
The bars for the intervals must be separated by visible gaps.

Written response

1 point

Treat the data values 1, 3, 5, and 7 as a sample. What is the sample variance?

Written response

1 point

For the ordered data 3, 5, 6, 8, 11, 14, 18, 21, use the common quartile method that excludes the median when forming the two halves. What is the interquartile range? Enter the answer as a number.