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Statistics Review. Mean. The mean often means “average”. To find the mean: Take the sum of the numbers divided by how many numbers. EXAMPLE: Class shoe sizes: 3, 5, 5, 6, 4, 3, 2, 1, 5, 6 Add up the numbers: 3 + 5 + 5 + 6 + 4 + 3 + 2 + 1 + 5 + 6 = 40 Divide by how many numbers:
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Mean • The mean often means “average”. • To find the mean: • Take the sum of the numbers divided by how many numbers. EXAMPLE: Class shoe sizes: 3, 5, 5, 6, 4, 3, 2, 1, 5, 6 Add up the numbers: 3 + 5 + 5 + 6 + 4 + 3 + 2 + 1 + 5 + 6 = 40 Divide by how many numbers: 40 ÷ 10 = 4 The class mean shoe size is 4
Median • The median is the middle value. • To find the median: • Put the numbers in order. Choose the number in the middle of the list. • If there are 2 numbers in the middle then it is halfway between them. • Find the number halfway between by finding the average of the two numbers. EXAMPLE: Class shoe sizes: 3, 5, 5, 6, 4, 3, 2, 1, 5, 6 Put in order: 1, 2, 3, 3, 4, 5, 5, 5, 6, 6 The class median shoe size is 4.5.
Mode • The mode is the most common number. • To find the mode: • Put the numbers in order. • Choose the number that appears the most frequently. • Sometimes there may be more than one mode or NO mode. EXAMPLE: Class shoe sizes: 3, 5, 5, 6, 4, 3, 2, 1, 5, 6 Put in order: 1, 2, 3, 3, 4, 5, 5, 5, 6, 6 The mode is 5.
Range • The range is the difference between the largest value and the smallest value. • To find the range: • Take the smallest number from the largest. EXAMPLE: Class shoe sizes: 3, 5, 5, 6, 4, 3, 2, 1, 5, 6 Subtract smallest from largest: 6 – 1 = 5 Range: 5
You Try! The stem-and-leaf plot shows the number of cans of food collected by students for a food drive. Number of Cans Collected 56 cans • What is the greatest number of cans collected? • What is the mode of the data? • 3. What is the mean? 32 cans 43 cans
Ms. Ruiz made a line plot to show the scores her students got on a test. Below is Ms. Ruiz's line plot. Test Scores x x x x x x x x What is the mode(s) score? 75 and 90 x x x x x x What is the range? 25 x x 85 What is the median score? x What is the mean of the test scores? 85.3 75 90 95 80 100 85
If the Milton family have $4000 this month for their budget then how much are they spending on each of things listed below? Food: .33 x 4000 =$1320 Rent: .25 x 4000 = $1000 Savings: .06 x 4000 = $240 Clothes: .15 x 4000 = $600 Misc. : .21 x 4000 = $840 Hint: Check your answer by making sure that they add up to $4000
Skills Check! When you finish turn your paper over and put it in the corner of your desk. No talking. Practice: Review worksheet