Practice Mode in Math

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

Quick Recap

The mode is the value or values that appear most frequently in a data set — it is the most common or most popular data value.

The mode is the "most popular" value — if you had to guess one number and wanted to be right as often as possible, pick the mode.

Showing a random 20 of 50 problems.

Example 1

easy
Find the mode of 4,4,4,9,94, 4, 4, 9, 9.

Example 2

medium
The data set {3,5,5,7,8,x}\{3, 5, 5, 7, 8, x\} has mean 5.55.5 and mode 55. Find xx.

Example 3

challenge
Explain why a perfectly uniform data set like 5,5,7,7,9,95,5,7,7,9,9 is ambiguous for the mode.

Example 4

medium
In {2,5,5,7,9,9,9,12}\{2, 5, 5, 7, 9, 9, 9, 12\}, find the mode and the gap between mode and mean.

Example 5

easy
Find the mode of {4,4,7,7,7,9,11}\{4, 4, 7, 7, 7, 9, 11\}.

Example 6

medium
The data 9,11,11,13,159, 11, 11, 13, 15 — find the mode and state whether it is unique.

Example 7

challenge
Construct a 1010-value data set where mode =2=2, median =5=5, and mean =10=10.

Example 8

medium
A frequency table lists: value 11 (count 4), value 22 (count 9), value 33 (count 9), value 44 (count 2). Find the mode.

Example 9

easy
Find the mode of {0,0,1,2,3}\{0, 0, 1, 2, 3\}.

Example 10

easy
In the data 10,10,20,30,30,3010, 10, 20, 30, 30, 30, find the mode.

Example 11

medium
In 3,5,5,7,7,7,9,x3, 5, 5, 7, 7, 7, 9, x, the unique mode is 77. What values of xx are allowed?

Example 12

easy
Find the mode of 5,6,7,85, 6, 7, 8.

Example 13

medium
Test scores: 80,80,85,90,90,95,10080, 80, 85, 90, 90, 95, 100. Compare mode, median, mean.

Example 14

medium
Find the mode of {2.1,2.1,2.1,3.0,4.5,5.0}\{2.1, 2.1, 2.1, 3.0, 4.5, 5.0\}.

Example 15

easy
True or false: the mode must be a value that appears in the data set.

Example 16

easy
Shoe sizes sold: 6,7,7,8,8,8,9,106, 7, 7, 8, 8, 8, 9, 10. Find the mode.

Example 17

medium
Find the mode of 2.5,2.5,3.1,3.1,3.1,4.02.5, 2.5, 3.1, 3.1, 3.1, 4.0.

Example 18

hard
For data set {x1,x2,,xn}\{x_1, x_2, \ldots, x_n\} with unique mode mm, prove that any data set you get by adding values m\ne m keeps the mode if you add fewer than (count of m)(next highest count)(\text{count of } m) - (\text{next highest count}) extra of any single value.

Example 19

medium
A data set a,a,b,b,b,ca, a, b, b, b, c has mode bb. After removing one bb, what is the new mode?

Example 20

hard
A data set has values {5,5,5,7,9,12}\{5, 5, 5, 7, 9, 12\}. If you append a value vv so the new set is bimodal with modes 55 and 77, what must vv be?