Algebra II : Mean
Study concepts, example questions & explanations for Algebra II
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Example Questions
Example Question #283 : Basic Arithmetic
Find the mean of the following numbers:
150, 88, 141, 110, 79
88
113.6
71
141
110
113.6
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 #11 : Mean
If you roll a fair die six million times, what is the average expected number that you roll?
4
2.5
3.5
4.5
3
3.5
The outcomes from rolling a die are {1,2,3,4,5,6}.
The mean is (1+2+3+4+5+6)/6 = 3.5.
Rolling the die six million times simply suggests that each number will appear approximately one million times. Since each number is rolled with equal probability, it doesn't matter how many times you perform the experiment; the answer will always remain the same.
Example Question #1 : How To Find The Missing Number In A Set
If the mean of the following set is 12, what is 
(1,14,3,15,16,
Since we are given the mean, we need to find the sum of the numbers. From there we can figure out 
We can use this to find the sum by plugging in
So our sum is 96.
So we know that our total sum minus the sum of the given numbers is equal to 
So, 
Example Question #284 : Basic Arithmetic
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?
71
90
98
95
82
98
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 #285 : Basic Arithmetic
The mean of the following set is 8. What is 
Cannot be determined
8
9
2
1
1
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 #12 : Mean
Angela scored the following on her past tests.
What is the current average (mean) score of her exams?
To find the average, add up all of the scores, then divide by how many scores there were:
Example Question #112 : Data Properties
The average score on a test that Sarah was absent for was 
Set 
Now set up an equation to solve for Sarah's test score:
Example Question #113 : Data Properties
In the Olympics gymnastics time trials, Sally's scores were 
Sally will make the team if she earns a
Sally will make the team if she earns a
Sally will only make the team if she makes a perfect ten.
Sally will make the team if she earns a
Sally will not make the team.
Sally will not make the team.
In order to determine whether Sally will qualify for the last time trial, set up an equation to find the mean. Out of the five scores, one of the scores is unknown, and Sally's final score must be 
Write the equation to solve for the mean.
Unfortunately, Sally cannot make the gymnastics team because she needs to earn a 10.8, which is not possible on the score limit.
The correct answer is:
Example Question #13 : Mean
Find the mean of the following set of numbers: 
The mean is also the average of a set of numbers. To find the mean, add all of the numbers in the set: 
In this case, the sum of all the numbers is 
This will give you an average or mean of 
Example Question #114 : Data Properties
The average of the class on the most recent exam was an 84.1. The 2 lowest scores of the class were 71 and 73. If the teacher decides to removed the 2 lowest scores from the class average and there are 10 students in the class, what is the new class average?
To get the total combined score of everyone in the class, multiply the average of the class by the number of students.
Now the new total is 697. To find the new average, divide this new total by the new number of grades to be averaged in, which is 8. Remember that the teacher dropped 2 grades so there are less grades to take into account.
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