Graphs Histogram, Circle, Box-Whisker Cornell Notes #11 Central Tendency Review

Choosing the Best Measure Which central tendency best represents a data set. Mean is usually the best choice. HOWEVER: if there is a outlier ( a number that is much lower or higher than the others) the median or mode is a better choice.

Choosing the Best Measure Example: The data set represents the number of customers that came into the restaurant last week. We want to estimate the number of customers that will come into the restaurant next week. Data Set: 88, 220, 253, 305, 306, 310, 310 Mean: 256 Median: 305 Mode: 310 Since there is an outlier (88), the mean is not the best choice. Median, Mode: best

Practice: The following data set shows the number of free throws Jordan had in each of his 12 years playing basketball. 67, 26, 20, 93, 78, 88, 79, 99, 64, 75, 74, 10 Is the mean, median, or mode best to use to describe this data set? Explain. Data Set: 10, 20, 26, 64, 67, 74, 75, 78, 79, 88, 93, 99 Mean: 64 Median: 74.5 Mode: none Mean: not a good choice- outlier of 10 Mode: none Median: best choice

Representations of Data In this lesson, you will take notes on how to construct and interpret histograms and circle graphs. You will also learn how to choose the best graph to represent different types of data.

Circle Graphs Circle Graph Graphs that represents parts of a whole. Sum of the angle measures equal 360˚ Multiply the percent in each section by 360 to find the angle measure.

Find the number of each of the equations. Circle Graphs Find the number of each of the equations. Convert the percent to a decimal. 40% to a decimal 40 ÷ 100=.40 8% to a decimal 8 ÷ 100=.08 40% of 25= 25% of 30= 67% of 66= 8% 0f 23= 10% of 100 1% of 56=

200 boxes of fruit were sold. 27% apples 8% grapes 3% pears Circle Graphs Example: 200 boxes of fruit were sold. 27% apples 8% grapes 3% pears 40% oranges 22% other Percent’s equal 100% Find the number of boxes of each fruit. 200 X 27% (.27) 54 boxes of apples 200 X 8% (.08) 16 boxes of grapes 200 X 3% (.03) 6 boxes of pears 200 X 40% (.40) 80 boxes of oranges 200 X 22% (.22) 44 boxes of other fruit

200 boxes sold: what percent of apples sold? Circle Graphs Example: 200 boxes sold: what percent of apples sold? To find the percent sold: Number sold ÷ total=% of total. 54 boxes of apples: 54 ÷ 200=.27 or 27% 6 boxes of pears: 6 ÷ 200=.03 or 3% .03 X 100=3%

Sum of all fruit is 100%

Histograms Histograms Used to show continuous data. Intervals are shown across the bottom. The heights of the bars shows how many times something happens.

Histogram Example: Score between 0 and 10 occurred 1 time, 11-20 occurred 2 times (range of scores)

Summary Graphs Histogram Circle graph Box-and –whisker plot Representation Purpose of data Histogram Comparing amounts of continuous data: Type of bar graph Circle graph Comparing parts of a whole Sum of all parts is 100% Box-and –whisker plot Showing how data are distributed