Mean Absolute Deviation Teacher Twins 2015 Warm Up
Mean Absolute Deviation Teacher Twins © 2015
Warm Up Tell which measure of central tendency best represents the data. 1). How many pairs of shoes do you have? How is the The data is skewed left. data skewed? The best measure is the median because it is slightly skewed. 2). How many hours do you play video games daily? How is the data skewed? The data is somewhat symmetrical. Both the mean and median represent the data.
Mean Absolute Deviation is the average distance between each piece of data and the mean. The MAD is a measure of variation. Measures of variation describe how data values vary by using a single number.
How to Find the Mean Absolute Deviation or MAD 1). Find the mean. 2). Find the distance between each piece of data and the mean. Remember distance is not negative so take the absolute value of the difference. 3). Find the average of the differences.
Example 1: Find the mean absolute deviation of the daily visitors to the local park for one week. 234, 540, 502, 629, 530, 450, 574 260. 1, 45. 9, 7. 9, 134. 9, 35. 9, 44. 1, 79. 9 Find the average. 494. 1 Find the distance each piece of data is from the average. Find the average of the differences. MAD is 87
Example 1: Find the mean absolute deviation of the daily visitors to the local park for one week. 234, 540, 502, 629, 530, 450, 574 260. 1, 45. 9, 7. 9, 134. 9, 35. 9, 44. 1, 79. 9 The mean number of visitors to the park is 494 visitors per day. The MAD is 87 which means the average distance from each piece of data is 87 visitors above or below the mean. This shows the spread of the data. The MAD is a higher number because of 234 which is an outlier.
Example 2: Find the mean absolute deviation of the price of movie tickets. $5. 75, $5. 00, $6. 50, $7. 00, $9. 50 $1. 38 $2. 13 $0. 63 $0. 13 $1. 87 $2. 37 Find the average. $7. 13 Find the distance each piece of data is from the average. Find the average of the differences. The MAD is $1. 42. This means the spread of data is about $1. 42 from the mean.
Example 2: Find the mean absolute deviation of the price of movie tickets. $5. 75, $5. 00, $6. 50, $7. 00, $9. 50 $1. 38 $2. 13 $0. 63 $0. 13 $1. 87 $2. 37 The mean number for the price of a movie ticket is $7. 13. The MAD is $1. 42 which means the average distance from each price of a movie ticket is $1. 42 above or below the mean. This shows the spread of the data.
Practice Find the mean absolute deviation. Round to the nearest tenth. Explain what the MAD tells you about the spread of the #2 ). The MAD is 2. 8 which means the average distance from data. each amount spent on homework is 2. 8 away from the mean. The MAD is high because of the outlier. 1). Number of Pets per household 4, 5, 8, 0, 3, 2 The MAD is 2 which means the average distance from each number of pets is 2 away from the mean. 2). Hours spent per week on homework 15, 6, 2, 8, 9, 7
Closure What does the mean absolute deviation tell you about your data?
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