AP Statistics - Weebly



AP Statistics

Notes: Constructing and analyzing graphs

Displaying Quantitative Data:

Histograms:

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Example: Wake County SAT scores for 2007

1403 1419 1490 1494 1515 1539 1540 1547

1547 1598 1609 1616 1623 1634 1643 1737

Determining the bin size:

Number of observations: Max: Min:

Range: [pic]

Bin size:

Description of data:

Questions:

1. How many schools scored fewer than 1500 points on the SAT?

2. How many schools scored 1600 points or higher?

3. How many school scored between 1500 and 1700 points?

Ojive (Relative cumulative frequency graph)

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Example: SAT Data

Creating a graph:

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Practice: National SAT score

National SAT Scores

Create a histogram of the data

• Choose your bin size and alignment to best fit the data

Describe the distribution:

Fill in the table below using the information in the histogram

• Click on the top of each column to find the frequencies

Create an ojive (relative cumulative frequency plot) of the data

State SAT rankings are worse than meaningless, say Ball State experts (8/24/2001)

MUNCIE, Ind. - Ranking states according to their SAT averages is “worse than meaningless,” warn two Ball State University education experts who have researched the differences between states.

The College Board is expected to make its annual announcement of the SAT averages for the 50 states and the District of Columbia on Aug. 28. That announcement usually leads many people to start ranking the states from best to worse.

“The state SAT rankings are worthless in determining the quality of the schools in a state, and the potential for basing perceptions and policies on the rankings is even worse,” said Greg Marchant, a Ball State educational psychology professor.

A study by Marchant and colleague Sharon Paulson to be published in the October issue of the BULLETIN spells out problems with using a state's SAT ranking as an indicator of the quality of its education system. The journal is a research publication for high school administrators.

Marchant and Paulson determined the rankings say more about the nature of the students taking the test in each state than about the states' educational systems. The study examined the characteristics of individuals taking the SAT and compared the 10 highest scoring states with the 10 lowest scoring states.

They found the larger the percentage of students taking the SAT in a state, the lower the average SAT.

In the 10 states with the highest SAT scores, an average of 8 percent of their high school students took the SAT, while 69 percent of students took the test in the 10 lowest scoring states.

Also, the lowest 10 states had twice as many high school juniors taking the test and 14 times as many SAT takers overall.

“The states with the highest SAT scores and lowest percentage of SAT takers tend to be testing mostly their best and brightest,” Marchant said. “There is more diversity in the ability of test takers that come from the lower scoring states. In the top scoring states, twice as many test takers come from the top 10 percent of their class. Test takers from lower scoring states represent a far greater range of both class rank and grade-point average.”

The more a state's education system works to increase college attendance for students who have traditionally not pursued higher education, the lower the state's average SAT scores are likely to be, Marchant added.

Differences in parent income and parent education of the test takers accounted for 92 percent of the difference among the states' average SAT scores.

The bottom 10 scoring states had more than 41 times as many test takers from families with incomes less than $10,000.

“This is major issue for high school students attempting to be first-generation college students,” Marchant said.

Compared to the highest scoring 10 states, the bottom 10 states had more than 31 times as many test takers with parents holding only a high school diploma and more than 60 times as many test takers with parents who did not graduate from high school.

“Policy-makers and the general public are likely to be misled about the relative quality of a state's education system,” Marchant said. “They do not understand that the rankings reflect the characteristics of the students taking the test. This confusion can lead to erroneous policy decisions and false perceptions.”

Copyright © 2008 Ball State University   2000 W. University Ave. Muncie, IN 47306

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|Class |Frequency |

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|Class |Frequency |Relative Frequency |Cumulative |Relative |

| | | |Frequency |Cumulative |

| | | | |Frequency |

|1400-1449 |2 | | | | | |

|1450-1499 |2 | | | | | |

|1500-1549 |5 | | | | | |

|1550-1599 |1 | | | | | |

|1600-1649 |5 | | | | | |

|1650-1699 |0 | | | | | |

|1700-1749 |1 | | | | | |

Total: 16

Locating an individual:

Middle Creek’s score was 1515 what percentile?

What is the 50th percentile schools score?

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What percentile would a score of 1600 fall?

What score would place you at the 85th percentile?

How did Wake county score compared to the national average of 1518?

|Class |Frequency |Relative Frequency |Cumulative |Relative |

| | | |Frequency |Cumulative |

| | | | |Frequency |

|1350-1399 | | | | | | |

|1400-1449 | | | | | | |

|1450-1499 | | | | | | |

|1500-1549 | | | | | | |

|1550-1599 | | | | | | |

|1600-1649 | | | | | | |

|1650-1699 | | | | | | |

|1700-1749 | | | | | | |

|1750-1799 | | | | | | |

|1800-1849 | | | | | | |

Total:

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