1. Quick Start Expectations 1.Fill in planner and HWRS HW: p. 22, #9-16 2.Get a signature on HWRS 3.On desk: calculator, journal, HWRS, pencil, pen, 4.Warm Up: in journal together…

2. Exploring Quartiles DriverYearSpeed (MPH) Arie Luyendyk1990185 Rick Mears1991176 Bobby Rahal1986170 Juan Montoya2000167 Emerson Fittipaldi1989167 Helio Castronoves2002166 Rick Mears1984163 Mark Donahue1972162 Al Unser1987162 Tom Sneva1983162 Fastest winning speeds of the Indy 500

3. 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. (166 + 167) / 2 = 166.5

4. 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 170 162 162, 162, 162, 163, 166, 167, 167, 170, 176, 185

5. 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

7. Use on tonight’s HW!

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

12. Range = 68 mi/h Range = 41 mi/h Mean = 55.03 mi/h Mean = 52.6 mi/h

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

14. 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

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

17. 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.