1. Warm Up /1
Which of the following statements is true given the dot plot?
The distribution is skewed left, so the mean is greater than the median
The distribution is skewed left, so the mean is less than the median
The distribution is skewed right, so the mean is greater than the median
The distribution is skewed right, so the mean is less than the median
Get your homework out to be checked: p.557 #11, 13, 14

2. HW Check
Questions?

4. 0.2637 same as mean because symmetric

6. *IMPORTANT CONCEPTS*
Mean is pulled away from median in direction of the skew (tail)
When skewed right, mean > median
When skewed left, mean < median
Normal distribution: symmetric, unimodal, bell-shaped
Scale on a normal curve: mean = peak; +/- standard deviation for every tic mark

8. In 68% of the years from 1964 to 2013, the team batting average for St
In 68% of the years from 1964 to 2013, the team batting average for St. Louis Cardinals was between and 0.273

9. 95% between 0.245 and 0.283 99.7% between 0.235 and 0.293 2.5%
**what is the best estimate of the proportion of batting averages that are less than or equal to ?
2.5%

10. *IMPORTANT CONCEPTS*
Mean is pulled away from median in direction of the skew (tail)
When skewed right, mean > median
When skewed left, mean < median
Normal distribution: symmetric, unimodal, bell-shaped
Scale on a normal curve: mean = peak; +/- standard deviation for every tic mark
rule (normal distribution)
Percentages that fall within +/- 1, 2, and 3 standard deviations
Can only use if it falls exactly on 1, 2, or 3 standard deviations away (if not use z-scores)
𝒛−𝒔𝒄𝒐𝒓𝒆= 𝒗𝒂𝒍𝒖𝒆−𝒂𝒗𝒆𝒓𝒂𝒈𝒆 𝒔𝒕𝒂𝒏𝒅𝒂𝒓𝒅 𝒅𝒆𝒗𝒊𝒂𝒕𝒊𝒐𝒏 ; find z-score on table (pg. 576)

11. 𝒛−𝒔𝒄𝒐𝒓𝒆= 𝒗𝒂𝒍𝒖𝒆−𝒂𝒗𝒆𝒓𝒂𝒈𝒆 𝒔𝒕𝒂𝒏𝒅𝒂𝒓𝒅 𝒅𝒆𝒗𝒊𝒂𝒕𝒊𝒐𝒏 𝟎.𝟐𝟔𝟗−𝟎.𝟐𝟔𝟑𝟕 𝟎.𝟎𝟎𝟗𝟔 =𝟎.𝟓𝟓𝟐
Z-table pg. 576

12. 𝟎.𝟓𝟓𝟐
 70.88%

13. On your own/with a partner