ACT Math : Data Analysis

Study concepts, example questions & explanations for ACT Math

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Example Questions

Example Question #91 : Data Analysis

What is the median of the following list of numbers?

\displaystyle 1, 17, 23, 12 ,45, 4, 18, 21, 10, 9, 5

Possible Answers:

\displaystyle 15

\displaystyle 17

\displaystyle 12

\displaystyle 10.33

There is no median.

Correct answer:

\displaystyle 12

Explanation:

To find the median of a data set, line up all the numbers and find the number in the middle. If two numbers are in the middle (only true of even-numbered data sets) then take the average of the middle two.

\displaystyle 1, 17, 23, 12 ,45, 4, 18, 21, 10, 9, 5

\displaystyle 1, 4, 5, 9, 10,{\color{Red} 12} ,17, 18, 21, 23, 45

Since our data set has an odd number of numbers, the median is 12.

Example Question #91 : Data Analysis

Find the median of the following set of numbers.

Possible Answers:

\displaystyle 13

\displaystyle 15

\displaystyle 2

\displaystyle 8

Correct answer:

\displaystyle 8

Explanation:

To find the median, simply sort the numbers from smallest to largest and then find the number in the middle. Since these are already sorted, the answer is \displaystyle 8.

Example Question #92 : Data Analysis

Find the median of the following set of numbers:

\displaystyle 3,5,8,9,11,12,15,17

Possible Answers:

\displaystyle 10

\displaystyle 9,11

\displaystyle 9

\displaystyle 11

Correct answer:

\displaystyle 10

Explanation:

To find the median, simply find the middle number.

Since there are an even number of values, you will have to take and average of the two middle numbers.

Thus,

\displaystyle \frac{9+11}{2}=10

Example Question #93 : Data Analysis

Find the median of the following set of numbers:

Possible Answers:

\displaystyle 5.5

\displaystyle 1

\displaystyle 5

\displaystyle 6

\displaystyle 8

Correct answer:

\displaystyle 5.5

Explanation:

To find median, simply find the middle number. Since there are two in the middle, find their average. Thus,

Example Question #1 : How To Find Mode

Gradechart

Refer to the chart above.  What is the mode for all of the exam scores?

Possible Answers:

77

84

85

83

72

Correct answer:

85

Explanation:

Mode is the value that occurs most often within a set of data.

Example Question #1 : How To Find Mode

What is the sum of the mean, mode, and median of the following set of data:

20, 25, 7, 40, 13, 15, 20, 28

Possible Answers:

75

52

61

40

20

Correct answer:

61

Explanation:

First, the data set must be put in order from smallest to largest

7, 13, 15, 20, 20, 25, 28, 40

Mean = sum of data ÷ number of data points = 21

Mode = number occuring most often = 20

Median = middle number, or the mean of the two middle numbers = 20

Therefore, the sum of the mean, mode, and median is 61

Example Question #1 : How To Find Mode

What is the mode of the following set of data? 

{1, 3, 5, 3, 1, 6, 7, 3} 

Possible Answers:

6

3

5

2

1

Correct answer:

3

Explanation:

The most common element of the set of data is 3. It occurs three times, and no other number occurs 3 times.

Example Question #2 : How To Find Mode

\displaystyle \left \{ {23,27,28,21,24,29,21,30} \right \}

What is the mode of this set of numbers?

Possible Answers:

\displaystyle 21

\displaystyle 25.375

\displaystyle 25.5

\displaystyle 27

\displaystyle 208

Correct answer:

\displaystyle 21

Explanation:

The mode is the most commonly occuring number in a group of numbers.  \displaystyle 21 is the only number that occurs more than once.  

Example Question #4 : Mode

What is the mode of the following list of test scores: \displaystyle 80, 76, 93, 89, 93, 77

Possible Answers:

\displaystyle 84.5

There is no mode

\displaystyle 80

\displaystyle 93

\displaystyle 77

Correct answer:

\displaystyle 93

Explanation:

The mode is the most frequently occurring number. Thus it is 93 as that is the only repeated number.

Example Question #1 : Mode

The following is a list of the ages of \displaystyle 10 people randomly selected off the street:


What is the mode of the data set?

Possible Answers:

\displaystyle 31.36

\displaystyle 12

\displaystyle 30.5

\displaystyle 73

Correct answer:

Explanation:

The mode is the most frequently occuring number in the data set. This data set has only unique numbers, so there is no frequently occuring number. Thus there is no mode.

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