Measures of Variation Teacher Twins 2015 Warm Up

Measures of Variation Teacher. Twins© 2015

Warm Up 1). Create a histogram of the data. 2). Describe the spread of the data. 3). Find the median of the data. Test Score 100 -91 90 -81 80 -71 Frequency 5 8 4

2 4 6 8 10 1). Frequency Warm Up 100 -91 90 -81 80 -71 Test Score 2). Describe the spread of the data. The data is symmetrical 3). Find the median of the data. The median is 90 -81.

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Measures of Variation are used to describe the distribution of data. We have already learned about one measure of variation called the range. The range is the difference between the largest data value and the smallest.

To find the range you need to use the extremes. Lower Extreme Upper Extreme 2, 4, 5, 6, 7, 8, 11, 15, 16, 20 Lower Extreme or Minimum- Lowest number in set of data. Upper Extreme or Maximum- Highest number in set of data.

Quartiles are the values that divide the data into quarters. UQ LQ 2, 4, 5, 6, 7, 8, 11, 15, 16, 20 Lower quartile (LQ) The median of the lower half of a set of data also called Q 1. Upper Quartile (UQ) The median of the upper half of a set of data also called Q 3.

Quartiles 2, 4, 5, 6, 7, 8, 11, 15, 16, 20 Quartiles are the values that divide the data into quarters. IQR 15 -5 = 10

Example 1: 65, 78, 80, 89, 99, 100 Median- 84. 5 Lower Quartile- 78 Upper Quartile- 99 Interquartile Range- 99– 78 = 21 Upper Extreme- 100 Lower Extreme- 65

Example 2: 2, 3, 4, 6, 7, 8, 9, 11, 12 Median-7 Lower Quartile- 3. 5 Upper Quartile- 10 Interquartile Range-10 - 3. 5 =6. 5 Upper Extreme- 12 Lower Extreme- 2

Practice Prices of Movie Theatre Tickets $5. 00 $7. 50 $5. 75 $6. 00 $9. 50 $9. 00 $10. 00 $9. 00 Median- $7. 50 Lower Quartile- $5. 88 Upper Quartile- $9. 25 Interquartile Range- $3. 37 Upper Extreme- $10. 00 Lower Extreme- $5. 00

Closure Explain how you find the interquartile range of the following set of data. 176, 156, 143 , 155, 167, 180