Diablo ValleyCollege Fall 2004

Business Division Business 240

Bus 240 Exam 1 Your Name:______

Your Section: ______

General instructions: read all questions carefully and answer them thoughtfully, completely, yet concisely. This exam is worth 15 points. Each part of each question is labeled for its respective value. Use the back of each page to answer the questions when necessary.

  1. [3 points] In the academic year 2002 – 2003 there is a correlation coefficient of 0.72 between a female student’s age and a female student’s GPA for all DVC female students in the Business Division. Interpret the meaning of this finding—both by nature and extent of the association between the two variables, age and GPA, for female students.

  1. [4 points] The following table is not a proper frequency distribution. However, for students between the ages of 20 and 64, it is. This data is a head count and percentage of persons who attended the colleges of Contra Costa in two different fall semesters.

Age / Fall 2001 / Fall 1999
< 20 years / 7,319 / 11.00% / 1,450 / 2.30%
20 - 24 years / 37,508 / 56.50% / 39,157 / 61.20%
25 - 29 years / 6,790 / 10.20% / 7,790 / 12.20%
30 - 34 years / 3,519 / 5.30% / 3,720 / 5.80%
35 - 39 years / 2,552 / 3.80% / 2,751 / 4.30%
40 - 44 years / 2,433 / 3.70% / 2,549 / 4.00%
45 - 49 years / 2,170 / 3.30% / 2,304 / 3.60%
50 - 54 years / 1,820 / 2.70% / 1,717 / 2.70%
55 - 59 years / 1,115 / 1.70% / 1,172 / 1.80%
60 - 64 years / 552 / 0.80% / 607 / 0.90%
65+ years / 585 / 0.90% / 776 / 1.20%

a)[1 point] How would you calculate the total number of persons who attended classes at the colleges of Contra Costa in the Fall of 1999?

b)[1 point] What is the “shape” of this—Fall 1999—distribution, by age? Explain.

c)[1 point] What is the largest “class”, by age?

d)[1 point] Which class underwent the largest growth between Fall 1999 and Fall 2001?

  1. [4 points] The following pie charts contain the number of students who passed English courses at DVC by gender during two different semesters. Comment on the chages in the distribution of passing students by gender over the past four years for DVC English courses.

  1. [4 points] The following table presents some statistical measures for GPA from two samples of DVC student’s, by age, who stated they are here with the objective to “transfer” to a 4-year higher education institution:

Statistic / 25 and Under / Over 25
Mean / 2.69 / 2.94
Median / 2.77 / 3.01
Standard Deviation / 0.38 / 0.39

a)[1 point] Which age group has a better academic performance as measured by GPA? Explain.

b)[2 point] Which group’s academic performance has greater dispersion? (Hint: Use relative as well as absolute measures of dispersion in your response) Explain.

c)[1 point] Which group’s GPA distribution should be more skewed and in which direction are GPA’s skewed for each group? Explain.