1. Warm Up Find the mean, median & mode of the data sets: 1)11, 7, 19, 25, 7, 12, 13, 21, 18 2)25, 18, 23, 20, 31, 23

2. Homework Check 2.3

3. Measures of Center: Mean

4. Describing Data Numerically Measures of Center Median, mean

5. Thinking About the Situation

6. Mean You can also think of mean as a balancing point, or making sure everyone has the same amount.

7. The Formula

8. Investigation 2: Using the Mean

9. Investigation 3: Using the Mean 1)Find the following: a)the total number of students b)the total number of movies watched c)the mean number of movies watched 2)A new value is added for Carlos, who was home last month with a broken leg. He watched 45 movies. a)How does the new value change the distribution on the histogram? b)Is this new value an outlier? Explain. c)What is the mean of the data now? d)Compare the mean from question 1 to the new mean. What do you notice? Explain. e)Does this mean accurately describe the data? Explain.

10. 3)Data for eight more students is added. a)Add these values to the list in your calculator. How do these values change the distribution on the histogram? b)Are any of these new values outliers? c)What is the mean of the data now?

11. How do I know which measure of center to use?

12. Investigation 4: Mean vs. Median The heights of Washington High School’s basketball players are: 5 ft 9in, 5 ft 4in, 5 ft 7 in, 5ft 6 in, 5 ft 5 in, 5 ft 3 in, and 5 ft 7 in. A student transfers to Washington High and joins the basketball team. Her height is 6 ft 10in. Discuss and solve in your groups!

13. Mean vs. Median Mound-shaped and symmetrical (Normal) Skewed Left Skewed Right

14. Ticket out the Door What happens to the mean of a data set when you add one or more data values that are outliers? Explain. What happens to the mean of a data set when you add values that cluster near one end of the original data set? Explain. Explain why you think these changes might occur.

15. Coming up…  HW 2.4  QUIZ Friday!