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Unformatted text preview: Stat131a Dr. Wong Practice Final Exam May 3, 2004 Spring Semester 2004 UC Berkeley These questions are meant to give you practice for preparing for the final exam on Saturday, May 15, 8 am to 11 am. They are not meant to be comprehensive; i.e. you should not rely on studying just these questions for the final exam. Answers to the questions are provided in boxes. 1. Which of the following statements about correlation is false ? (a) The value of correlation coefficient is heavily influenced by outliers. (b) The correlation coefficient can never be larger than 1. (c) The correlation coefficient measures how tightly the points in a scatter plot cluster about a straight line. (d) The correlation coefficient cannot be 0. ans. (d) The correlation coefficient cannot be 0 is False The next three questions are based on the following information: Scores on the 1992 SAT verbal exam were normally distributed, with mean 480 and standard deviation about 100. 2. The median score was (a) 100 (b) 680 (c) 480 (d) cannot be determined without more information ans. (c) 480 3. What percent of all students scored between 380 and 580? (a) 68% (b) 95% (c) 75% (d) 99% ans. (a) 68% 4. What percent of all students scored above 580? (a) 32% (b) 16% (c) 75% (d) cannot be determined without more information (b) 16% Page 1 of 8 Continue on next page ... Stat131a Dr. Wong Practice Final Exam May 3, 2004 Spring Semester 2004 UC Berkeley 5. The correlation between average monthly temperature x and monthly natural gas consumption y over a period of months at Lincoln High School is 0.86. Which of the following operations would change the value of the correlation? (a) Measure gas consumption in cubic meters instead of cubic feet. (b) Remove two outliers from the data before doing the calculation. (c) measure temperature in degrees Kelvin instead of in degrees Fahrenheit. (d) All of (a), (b), and (c) would change the value of the correlation. ans. (b) Remove two outliers from the data before doing the calculation. 6. According to the student newspaper, the mean salary of male full professors in the School of Management is $117,302. The median of these salaries (a) would be lower, because salary distributions are skewed to the left. (b) would be lower, because salary distributions are skewed to the right (c) would be higher, because salary distributions are skewed to the left (d) would be higher, because salary distributions are skewed to the right ans. (d) would be lower, because salary distributions are skewed to the right 7. What can we say about the relationship between a correlation r and the slope b of the least squares line for the same set of data? (a) r is always larger than b (b) r and b always have the same sign (+ or ) (c) b is always larger than r (d) b and r are measured in the same units ans. (b) r and b always have the same sign (+ or ) Page 2 of 8 Continue on next page ... Stat131a Dr. Wong Practice Final Exam May 3, 2004 Spring Semester 2004 UC Berkeley The next 7 questions concern the stem plot of the percent of adult males who are illiterate in 142...
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This note was uploaded on 10/31/2009 for the course STAT 131A taught by Professor Isber during the Spring '08 term at University of California, Berkeley.
 Spring '08
 ISBER
 Statistics

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