Algebra 1 : Statistics and Probability
Study concepts, example questions & explanations for Algebra 1
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Example Questions
Example Question #31 : Statistics And Probability
Eric's algebra class has 5 exams this semester. Eric scored 84, 90, 88, and 95 on his first four exams. What is the minimum score he must earn on the fifth exam to get an average score of 90 or above?
To get an average score of 90, the sum of Eric's test scores must equal 450 
Example Question #32 : Statistics And Probability
We have the following set of numbers: 13, 19, 14, 16, 11, 7, 4, 13, 18, 2, 13, 9, 9, 13.
Find the mean.
Finding the mean is just finding the average. To find the average and thus, the mean, add all of the numbers to get the total and then divide that total by a number that represents how many numbers make up the set. In this problem, the total is calculated as
Since there are 14 numbers making up the set, we divide 161 by 14 to get 11.5.
Example Question #33 : Statistics And Probability
Calculate the mean of the following set of numbers:
To determine the mean of a set of numbers, first add up all of the numbers in that set. Then divide the sum (40) by the amount of numbers in the original set (8).
Example Question #34 : Statistics And Probability
Find the average of the set 
2.5
3.5
2
1.2
2.5
To find the average of the set, we add up all of the elements of the set and then divide by the number of elements in the set. In our case, the number of elements is 8.
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?
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 #35 : Statistics And Probability
This semester, Ned earned scores of 78, 84, 90, and 92 on his algebra exams. What is Ned's average score?
To find Ned's average score, you must take the sum of his test scores and divide it by the number of tests. The sum of Ned's scores is 344 and he took 4 tests. Therefore, his average test score must be 86
Example Question #36 : Statistics And Probability
Find the mean of the following set:
To find the mean (average) of a set, add up all the numbers, which is 217. Then, divide by the number of terms you have (7). This results in 31.
Example Question #37 : Statistics And Probability
Consider the following numbers:
42, 51, 62, 47, 38, 50, 54, 44
The value 48.5 represents:
The median
Both the mean and the median
Neither the median nor the mean
The mean
Both the mean and the median
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 #38 : Statistics And Probability
Find the mean of the following numbers:
150, 88, 141, 110, 79
141
88
110
113.6
71
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 #39 : Statistics And Probability
If you roll a fair die six million times, what is the average expected number that you roll?
3
2.5
4
3.5
4.5
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.
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