Basic Arithmetic : Mean

Study concepts, example questions & explanations for Basic Arithmetic

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Example Questions

Example Question #11 : Mean

Find the mean of the following set of numbers: 32, 23, 46, 52, 37. 

Possible Answers:

Correct answer:

Explanation:

To find the mean, or average, of a set of numbers, you first add all of the numbers together:

.

Then, you divide the sum by the total number of numbers, which in this set is 5 (i.e., there are 5 numbers in this set):

.

38 is the mean, or average, of this set of numbers.

Example Question #12 : Mean

This semester, Reese must take 4 exams for his algebra class. On his first 3 exams, he scored a 73, 79, and 83. What is the minimum score he must earn on his fourth exam to get an average of 80 or higher?

Possible Answers:

Correct answer:

Explanation:

To calculate the average score, you must take the sum of Reese's scores and divide it by the number of tests he took (4). To get an average of 80, the sum of Reese's scores must be 320.

The sum of his first three test scores is 235.

Thus, Reese must earn a score of 85 on his fourth test

Example Question #12 : Mean

Consider the following numbers:

42, 51, 62, 47, 38, 50, 54, 44

The value 48.5 represents:

Possible Answers:

Neither the median nor the mean

The median

Both the mean and the median

The mean

Correct answer:

Both the mean and the median

Explanation:

First, calculate the mean. Sum the values and divide by the total number of values:

Next, determine the median. Reorder the values in ascending order:

38, 42, 44, 47, 50, 51, 54, 62

The median is the middle number. In this case, there is no "middle" number because we have an even number of values. Therefore, both 47 and 50 are the "middle". Average these numbers:

Therefore, 48.5 represents both the mean and median.

Example Question #13 : Mean

Find the mean of the following numbers:

150, 88, 141, 110, 79

Possible Answers:

71

141

113.6

 

88

110

Correct answer:

113.6

 

Explanation:

The mean is the average. The mean can be found by taking the sum of all the numbers (150 + 88 + 141 + 110 + 79 = 568) and then dividing the sum by how many numbers there are (5).

Our answer is 113 3/5, which can be written as a decimal.

Therefore 113 3/5 is equivalent to 113.6, which is our answer.

Example Question #203 : Algebra Ii

Reginald has scores of {87, 79, 95, 91} on the first four exams in his Spanish class. What is the minimum score he must get on the fifth exam to get an A (90 or higher) for his final grade?

Possible Answers:

82

95

71

98

90

Correct answer:

98

Explanation:

To find the fifth score, we need to set the average of all of the scores equal to 90.

Multiply both sides of the equation by 5.

Subtract 352 from both sides of equation.

Example Question #204 : Algebra Ii

The mean of the following set is 8. What is ?

 

Possible Answers:

Cannot be determined

9

2

8

1

Correct answer:

1

Explanation:

Let .

We know the mean is 8, and there are five values in the set, including the unknown .

Simplify.

Plug back into equation at top.

Example Question #17 : Mean

If the average of  numbers is  and the average of  numbers is , what was the number added to increase the average?

Possible Answers:

Correct answer:

Explanation:

If the average of  numbers is , then the sum is .

We also know the average of  numbers is . We can set-up an equation. 

.

The expression in the numerator represents the sum. By cross-multiplying, we get 

 or  as the final answer. 

Example Question #12 : Basic Statistics

If the average of  numbers is  and the average of  numbers is , what is the average of all the numbers?

Possible Answers:

Correct answer:

Explanation:

To find the average of all the numbers, we need to find the sums from each average. Since the average of  numbers is , that means the sum is .

The average of  numbers is  means the sum is .

Then, the total sum is  which is the sum of all the numbers.

So to find average, we do  divided by  to get 

Example Question #13 : Basic Statistics

Find the mean for the following set of numbers: 

, and 

Possible Answers:

Correct answer:

Explanation:

The mean is the same as the average. To find the mean, use the following formula:

Example Question #18 : Mean

Find the mean for the following set of numbers: 

, and 

Possible Answers:

Correct answer:

Explanation:

The mean is the same as the average. To find the mean, use the following formula:

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