The Statistics and Probability subarea accounts for 9% of the Mathematics Subtest. It includes 2 objectives. Let’s discuss one.
This section tests your ability to interpret and describe data and statistical information.
Here is a concept that is likely to appear on the test:
Measures of Central Tendency
The measure of central tendency is the typical value for a probability distribution. Measures of central tendency include:
This is the most popular measure. It is the average or norm or a data set. The mean is found by finding the sum of all numbers in a set then dividing the sum by how many numbers there are in the set.
Example: In the set 2, 2, 3, 5, 5, 5, 7, 8, then mean is 5.29. 2+2+3+5+5+5+7+8=37. 37 divided by 7 (the total number of values in the set) equals 5.29.
This is the middle value of a data set when the numbers are ordered from least to greatest.
Example: In the set 2, 2, 3, 5, 5, 7, 8, the median is five. If there is an even number of values in the data set, you average the middle two to find the median by adding them together and dividing by two.
This is the most frequent value in a data set. To find the mode, list all numbers in the set from least to greatest, then find the number that appears most frequently.
Example: In the set 2, 2, 3, 5, 5, 7, 8, the number 5 appears most frequently, so the mode is 5. If more than one number appears the most frequently, then each of those numbers would be included in the mode. If no numbers in the set appear more than once, then there is no mode.
The simplest way to find the spread in a data set is to find the range which is the difference between the least and greatest number in the set.
Example: In the set 2, 2, 3, 5, 5, 7, 8, the spread is six. The greatest number in the set is 8, and the number of least value in the set is 2. The difference between 8 and 2 is 6.