**Class 6: SAT scores**

**Part 1: SAT scores **

The Mills website facts page
gives the following information about SAT scores for the entering class in
2008-2009.

SAT range 1530-1860

(middle 50%)

1. If the Mills SAT scores are normally distributed, what is the mean and standard deviation for the scores for the entering class in 2008-2009?

2.
What percentile
would a student with a score of 1800 have among this Mills entering class?

3.
The following chart gives scores and percentiles
for all U.S. college bound senior women in 2008. How do these percentiles
correspond to percentiles for Mills entering class? Do the scores at Mills tend to be higher or lower than those
for all U. S. college bound seniors?

Percentile |
Score |

99 |
2200 |

97 |
2100 |

94 |
2000 |

89 |
1900 |

82 |
1800 |

78 |
1750 |

74 |
1700 |

63 |
1600 |

51 |
1500 |

38 |
1400 |

16 |
1200 |

4 |
1000 |

1 |
800 |

4.
Suppose a
college uses SAT scores as a major component of their admissions process. Would you expect SAT scores to be
normally distributed for entering students at this college? What about for a school that doesnÕt
pay much attention to SAT scores?
What about Mills?

**Part 2: Height and Weight
Percentiles**

Look at the chart of height
percentiles by age.

1.
What is the
median height for a 20 year old?

2.
Based on this
chart, do you think heights are normally distributed for each age? Explain.

3.
Estimate the
standard deviation for height for a 20 year old.

4.
What is the percentile
for a 20 year old with a height of 5Õ10Ó (178 cm)?

5.
Why do the
percentile lines go up from age 18 to 20 and down from age 30 to 70?

Look at the chart of weight
percentiles by age.

1.
What is the
median weight for a 20 year old?

2.
Based on this
chart, do you think weights are normally distributed for each age? Explain.

**Journal Assignment: **

1.
Read the article
on SAT scores and family income from the NY Times blog. Why do you think SAT scores go up with
family income?

2.
Read the article
ÒKids who pick easy college often drop outÓ. Do you think picking an easy college caused students to drop
out at a higher rate? If so,
why? Do you think there was an
underlying factor that caused students to pick easier colleges and also caused
them to drop out at higher rates?
If so, what?

**Homework Assignment 6 for Thurs,
Sept. 17: **

On blackboard

**Announcements:**

Thursday will be a computer
lab. Tuesday weÕll have a quiz on
mean, median, standard deviation and experimental design.