1. Quiz 2.1 Clear your desk except for a pencil & calculator!

2. Warm Up 1) Find the mean & median for this data set: 7, 6, 5, 8, 10, 20, 4, 3 2) Which measure of center, the mean or median should be used to describe the data set? Why?

3. HW Check 2.4

4. You have 30 seconds to link together as many paper clips as possible!

5. Given our class data: 1)Create a frequency table 2)Create a histogram 3)Describe the distribution

6. Measures of Spread: Standard Deviation

7. Describing Data Two ways to describe data: Graphically Dot plot Histogram – Boxplot Numerically – Measures of Center: Median and Mean – Measures of Spread

8. Measures of Spread Range Interquartile Range (IQR) Standard Deviation How much do values typically vary from the center?

9. Consider the following test scores: Who is the best student? How do you know? StudentTest 1Test 2Test 3Test 4 Johnny658293100 Will82868983 Anna80997388

10. So who is the best?! Sometimes you need too look at more information than the measure of center… So we look at the SPREAD…

11. Measures of Spread One-Variable: Range Interquartile Range (IQR) Standard Deviation How much do values typically vary from the center?

12. Range  To find the range of a set of data you take the largest value in the data set and subtract the smallest number in the data set BIG # - small # = range

13. Lets focus on STANDARD DEVIATION Standard deviation measures the dispersion of data. The greater the value of the standard deviation, the further the data tends to be dispersed from the mean. Luckily, we can find the standard deviation on the calculator.

14. Back to our students... Lets calculating each of their Standard Deviations StudentTest 1Test 2Test 3Test 4 Johnny658293100 Will82868983 Anna80997388

15. Steps Step 1: Enter the height data in L 1. Commands: STAT  EDIT (Use 2 nd QUIT to exit) Step 2: Find your “best friend” in this unit Commands: STAT  CALC  1: 1-Var Stats  Enter

16. What do they all mean… Mean The sum of your data  Ignore this Standard Deviation  Ignore this Number of data entries

17. Who is the best student? How do you know? StudentTest 1Test 2Test 3Test 4 Test Average Standard Deviation Johnny6582931008513.2 Will82868983852.7 Anna80997388859.7 Now calculate the standard deviation of each and discuss…

18. HW 2.5