7.3 Mean, Median and Mode Learning Objectives: 1. Find the mean of a list of numbers. 2. Find the median of a list of numbers. 3. Find the mode of a list of numbers. 4. Key Vocabulary: measures of central tendency, mean, median, mode, grade point average (GPA), weighted mean. A. Finding the Mean Definition: Mean­is the sum of the items divided by the number of items. sum of items
Mean =
number of items
Steps of finding the mean­Add all numbers and divide by the number of the elements. Example 1. Find the mean of the following numbers: 1, 9, 27, 81, 243 and 3. B. Finding the Median Definition: Median­ is the middle number. If the number of items is odd, the median is the middle number. If the number of items is even, the median is the mean of the two middle numbers. Steps of finding the median: 1. Write numbers from the smallest to largest. 2. The median is the middle number. 3. If there is no middle number, then the median is the average of two middle numbers. Example 2. Find the median of the following numbers. 1. 1, 27, 8, 125, 64 2. 1, 3, 27, 81, 9, 243 C. Finding the Mode Definition: Mode—is the numbers that occurs most often. It is possible for a set of numbers to have more than one mode or to have no mode. Steps of finding the Mode: 1. The mode is the number that occurs most often. 2. In the set, we can have more than one mode. 3. If there is no number that occurs most often, then the set has no mode. Example 3. Find the mode(s) of the following numbers if there is one. 1. 29, 25, 22, 25, 52, 8 2. 2, 8, 8, 1, 2, 8, 2 3. 2, 7, 11, 8, 21, 18 D. Finding the Grade Point Average (GPA) Steps of finding your Grade Point Average (GPA): 1. Compute points earn: Points Earned = (Credit Hours)(Weight of Letter Grade) Total Po int s Earned
2. Compute GPA: GPA = Total Credit Hours
Example 4 Find the GPA for a student taking 13 hours at Montgomery College. Weight of grade: A = 4 points, B = 3 points, C = 2 points, D = 1 point, F = 0 points. If necessary, round the grade point average to the nearest hundredth. Course Credit Hrs (CH) Grade Points Earned PY102 3 A SO101 3 C BI101 4 B PE129 1 A HE107 2 B