Box and Whisker Plots An interactive lesson EQ

Box and Whisker Plots An interactive lesson EQ: How can you use a sample to gain information about a population? 7. SP. 2 – Use data from a random sample to draw inferences about a population with an unknown characteristics of interest. Generate multiple samples of the same size to gauge the variation in estimates or predictions.

Introduction • A box-and-whisker plot can be useful for handling many data values. • They allow people to explore data and to draw informal conclusions when two or more variables are present. • It shows only certain statistics rather than all the data. • Box and whisker plots consists of the median, the quartiles, and the smallest and greatest values in the distribution.

How to make a Box and Whisker Plot 1. Put your set of date in increasing numerical order (if it isn’t already). Example: 100, 27, 34, 59, 18, 52, 61, 78, 68, 82, 87, 85, 93, 91. Should now look like this … 18, 27, 34, 52, 54, 59, 61, 68, 78, 82, 85, 87, 91, 93, 100

Step 2 - Median 2. Find the median of your set of data *Remember the median is the value exactly in the middle of an ordered set of numbers* 18, 27, 34, 52, 54, 59, 61, 68, 78, 82, 85, 87, 91, 93, 100. Q: What would you do it you had an even set of numbers?

Step 3 – Lower Quartile 3. Next, we consider only the values to the left of the median 18, 27, 34, 52, 54, 59, 61, 68, 78, 82, 85, 87, 91, 93, 100. We find the median of those numbers 18, 27, 34, 52, 54, 59, 61 Q: This number is call the lower quartile. Can you guess why?

Step 4 – Upper Quartile 4. Next, we consider only the values to the right of the median 18, 27, 34, 52, 54, 59, 61, 68, 78, 82, 85, 87, 91, 93, 100. We find the median of those numbers 78, 82, 85, 87, 91, 93, 100. Q: This number is call the upper quartile. Can you guess why?

Step 5 – Highest/Lowest Values 5. Now indicate your lowest and highest values 18, 27, 34, 52, 54, 59, 61, 68, 78, 82, 85, 87, 91, 93, 100.

Step 6 - Drawing 6. Now we are ready to begin to draw our graph. 18, 27, 34, 52, 54, 59, 61, 68, 78, 82, 85, 87, 91, 93, 100. Plot the lowest value, lower quartile, median, upper quartile, and the highest value on a number line.

Put a line through the Lower Quartile, Median, and Upper Quartile. Then Put a box around those lines

Lastly draw a line from your extreme values to the box There is your Box and Whisker Plot Q: Can you guess where the graph gets it’s name?

• Time for a challenge activity with you shoulder buddy!

On your own! • Take the two data sets I passed out and glue in your notebook. • Find the median, upper quartile, lower quartile, upper value, and lower value. • Make a box and whisker plot with your data • We will check when all is done!

Analyze Date • The number of tigers observed, in a one-hour period, by a random sample of people was recorded. The data are represented below. Make a box plot and answer these few questions. • 4, 5, 6, 6, 7, 7, 8, 8, 9, 9

Analyze Data • 1) What was the median number of tigers observed? • 2)Every observer saw at least how many tigers? • 3)About what percent of the people saw anywhere from 6 to 8 tigers? • 4)About what percent of the people saw more than 8 tigers?