Lesson 5-8 Pages Measures of Central Tendency Lesson Check 5-7

What you will learn! 1.How to find the mean, median, and mode as measures of central tendency. 2.How to use the mean, median, and mode.

Measures of central tendency Mean Median Mode

What you really need to know! When working with numerical data, it is often helpful to use one or more numbers to represent the whole set. These numbers are called measures of central tendency.

StatisticDefinition Mean sum of the data divided by the number of items in the set Median middle number of the ordered set Mode number or numbers that occur most often What you really need to know!

Example 1: The revenue of the 10 highest grossing movies as of June 2000 are given in the table. Find the mean, median, and mode of the revenues. Top 10 Movie Revenues (millions of $)

Example 1: Mean ,798 3,798 ÷ $379.8 million

Example 1: Median = ÷ 2 = $343.5 million330357

Example 1: Mode No Mode This is no number or numbers that appear more than any other number. Therefore there is no mode

Example 2: The line plot on the next screen shows the number of gold medals earned by each country that participated in the 1998 Winter Olympic Games in Nagano, Japan. Find the Mean, median, and mode for the gold medals won.

Example 2: x x x x x x x x x xx x x x x x x x x x x xxx There are 24 numbers in this set of data!

Example 2: x x x x x x x x x xx x x x x x x x x x x xxx = 69

Example 2: x x x x x x x x x xx x x x x x x x x x x xxx 69 ÷ 24 = mean

Example 2: x x x x x x x x x xx x x x x x x x x x x xxx The numbers are all ready in order. Since there are 24 numbers, the median would be 12 from the top and bottom of the line plot. The median is 2.

Example 2: x x x x x x x x x xx x x x x x x x x x x xxx The mode is 0

Example 3: The quiz scores for a math class are 8, 7, 6, 10, 8, 8, 9, 8, 7, 9, 8, 0, and 10. Identify an extreme value and describe how it affects the mean.

Example 3: 0 is an extreme value. Mean with 0 is 7.5 Mean without 0 is 8.2 The 0 lowers the mean by 0.7 points

Example 4: The table shows the monthly salaries of the employees at two bookstores. Find the mean, median, and mode for each set of data. Based on the averages, which bookstore pays its employees better?

Bob’s Books The Reading Place ÷ ÷ 5 $1868$1600 Median Mode

Bob’s Books The Reading Place Mean$1,868$1,600 Median$1,400$1,550 Mode$1,400 No Mode The Reading Place pays its employees better.

Example 5: Jenny’s bowling average is 146. Today she bowled 138, 140, and 145. What does she need to score on her fourth game to maintain her average?

Example 5: = = – 423 = 161 Jenny needs to score at least 161 on her fourth game.

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Lesson Check 5-8