1. Do Now Find the mean, median, mode, and range of each data set and then state which measure of central tendency best represents the data. 1)2, 3, 3, 3, 4, 5, 6, 7, 7, 8, 9, 10, 13, 15, 15 2)12, 15, 51, 52, 53, 53, 56, 58, 58, 58, 61

2. Frequency Tables One way to organize the numbers in a data set is to make a frequency table. Frequency tables group the numbers in the data set together into fixed intervals. The frequency column tells how many numbers from the data set fall within each interval.

3. You cannot find the actual median using one of these tables, but you can find the interval that contains the median. 1)Figure out how many numbers you have. 2)Divide by 2 to find which value would be the median. (i.e. the 3 rd value out of 5) 3)Determine which interval would have that value (start with the lowest interval).

4. 1)2 + 3 + 4 + 2 = 11 values in the set 2)11/2 = 5.5, which means the 6 th value is the median. 3)20 – 39 has the 1 st and 2 nd values 40 – 59 has the 3 rd through 6 th values 60 – 79 has the 7 th through 9 th values 80 – 100 has the 10 th and 11 th values 40 – 59 contains the median

5. Try On Your Own!! 4)Which interval contains the median speed?

6. Quick Review – Box and Whisker Plots

7. Things To Know…  Each whisker contains 25% of the data  The box contains 50% of the data.  The interquartile range is difference between the upper and lower quartiles.

8. Examples 1)For a set of data, the interquartile range is 15 and the lower quartile is 33, what is the upper quartile? 2)For a set of data, the interquartile range is 23 and the upper quartile is 89, what is the lower quartile?

9. Examples 3)For a set of data, the interquartile range is 17 and the upper quartile is 56, which value could be the median? a) 39 b) 25 c) 63 d) 47