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Unformatted text preview: Name: Practice First Midterm Exam Statistics 1000 Spring 2007 (Pfenning) This is a closed book exam worth 150 points. You are allowed to use a calculator and a twosided sheet of notes. There are 9 problems, with point values as shown. If you want to receive partial credit for wrong answers, show your work. Dont spend too much time on any one problem. 1. (5 pts.) Suppose we are interested in finding out if students tend to sleep less, the older they are. (a) What would be an appropriate display? (i) bar graph (ii) histogram (iii)sidebyside boxplots (iv) scatterplot (b) Which of these would provide the best summary? (i) compare percentages (ii) compare means and standard deviations (iii) compare Five Number Summaries (iv) report the correlation 2. (5 pts.) Suppose we are interested in finding out if smokers exercise less than non smokers. Data values for exercise times include some high outliers. (a) What would be an appropriate display? (i) bar graph (ii) histogram (iii)sidebyside boxplots (iv) scatterplot (b) Which of these would provide the best summary? (i) compare percentages (ii) compare means and standard deviations (iii) compare Five Number Summaries (iv) report the correlation 3. (5 pts.) Suppose we are interested in finding out if males are just as likely as females to prefer the color black. (a) What would be an appropriate display? (i) bar graph (ii) histogram (iii)sidebyside boxplots (iv) scatterplot (b) Which of these would provide the best summary? (i) compare percentages (ii) compare means and standard deviations (iii) compare Five Number Summaries (iv) report the correlation 4. (10 pts.) Words per minute typed by experienced typists follows a normal distribution with mean 60 and standard deviation 15. (a) According to the 689599.7 Rule, 95% of experienced typists type between and words per minute. (b) Suppose an experienced typist can type 78 words per minute. What is his standard (z) score? 5. (20 pts.) Two banks each have three tellers helping customers. One bank requires customers to stand in separate lines for the three tellers, the other has customers stand in a single line and be called to the next available teller. Below are a backto back stemplot and sidebyside boxplot for waiting times (stems are minutes) of 10 customers at the bank with separate lines and 11 customers at the bank with a single line. Separate Single 1 4 6 2 5 7 2 6 6 7 7 9 7 7 7 1 2 3 4 7 8 8 5 8 3 9 10 11 (a) Judging from the looks of the stemplot, which arrangement seems to be faster?...
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This note was uploaded on 02/15/2012 for the course STAT 1000 taught by Professor Taeyoungpark during the Fall '06 term at Pittsburgh.
 Fall '06
 taeyoungpark
 Statistics

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