Teacher Notes This is a two day lesson. The Homework is not split up over the two days, but could be at your discretion. Students should have two days to do it. Get as far as you can on day 1, and do the rest on day 2.

Quick Start Expectations 1.Fill in planner and HWRS HW: p. 22, #9-16 (DUE THURSDAY) 2.Get a signature on HWRS 3.On desk: calculator, journal, HWRS, pencil, pen, 4.Switch to CC7 Books; clean up from yesterday, please! 5.TAKE OUT JOURNALS: Title Today’s Notes “Exploring Quartiles” What do you think quartiles are?

Exploring Quartiles DriverYearSpeed (MPH) Arie Luyendyk Rick Mears Bobby Rahal Juan Montoya Emerson Fittipaldi Helio Castronoves Rick Mears Mark Donahue Al Unser Tom Sneva Fastest winning speeds of the Indy 500

Finding the Inter-quartile Range (IQR) Step 1: Write the speeds in order from least to greatest. 162, 162, 162, 163, 166, 167, 167, 170, 176, 185 Step 2: Find the median of the data since the median separates the data into two halves. 162, 162, 162, 163, 166, 167, 167, 170, 176, 185 Since there are two numbers in the middle we have to find the mean of the two. ( ) / 2 = 166.5

Steps Continued… Step 3: Find the median of the upper half of the numbers________. This number is called the upper quartile. Circle this number in your step 1 and label it UQ Step 4: Find the median of the lower half of the numbers_______. This number is called the lower quartile. Circle this number in your step 1 and label it LQ , 162, 162, 163, 166, 167, 167, 170, 176, 185

Steps Continued… Step 5: The middle half of the data goes from the upper quartile (UQ) to the lower quartile (LQ). Subtract the LQ from the UQ. 170 – 162 = 8 This is called the inter-quartile range of the scores!! The IQR describes the variability of the middle 50% of the data values. 162, 162, 162, 163, 166, 167, 167, 170, 176, 185

More Practice! Roller Coaster Name/Location Year Opened Speed (MPH) Kingda Ka, Six Flags NJ Top Thrill Dragster, Cedar Point OH Dodonpa, Japan Superman, Six Flags CA Tower of Terror, Australia Steel Dragon, Japan Millennium Force, Cedar Point OH Goliath, Six Flags CA Titan, Six Flags TX Phantoms Revenge, Kennywood Park Xcelerator, Knott’s Berry Farm Fujiyama, Japan Thunder Dolphin, Japan

Find the Stats… Step 1: Order the data… 81, 81, 82, 82, 85, 85, 93, 95, 100, 100, 112, 120, 128 Range: 128 – 81 = 47 Median: 93 Upper Quarter (UQ): ( )/2 = 106 Lower Quartile (LQ): 82 Interquartile Range: 106 – 82 = 24 Mean: about 96 Mode: No mode because 81, 82, 85, 100 each appear twice Outliers: 128

P. 16

Use on tonight’s HW!

How might you decide which are faster, steel-frame roller coasters or wood-frame roller coasters?

Range = 68 mi/h Range = 41 mi/h Mean = mi/h Mean = 52.6 mi/h

Median = 54.5 mi/h Median = 53 mi/h IQR = 28 mi/h IQR = 10 mi/h Comparisons on next slide…

IQR for steel-frame is more than twice the IQR for the wood-frame The median of the steel-frame is greater than the median of the wood-frame The middle 50% of the speeds for steel- frame are more variable than the middle 50% for wood-frame

Box-and-Whisker Plots At least 25% of the steel-frame coasters have speeds that are faster than those of wood-frame coasters.

The measures of center for steel-frame and wood- frame coasters are somewhat similar. Speeds of steel-frame coasters vary greatly. Measures of spread (specifically IQR) show that at least 25% of the steel-frame coasters have speeds that are faster than those of wood-frame coasters.