# VCU STAT 210 - Test 2 Practice Test #3 (4 pages)

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## Test 2 Practice Test #3

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- Pages:
- 4
- School:
- Virginia Commonwealth University
- Course:
- Stat 210 - Basic Practice of Statistics

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Test 2 Practice Test 3 1 Identify which of the following choices is the appropriate description of the statistic listed It is possible to use a choice more than once A B C D A measure of center that is not resistant to outliers A measure of center that is resistant to outliers A measure of spread that is not resistant to outliers A measure of spread that is resistant to outliers Interquartile range Mean Median Range Standard deviation 2 Which of the following is a graphical procedure for displaying quantitative data A Stem and leaf plot B Histogram C Box plot D All of A B and C E None of A B and C 3 Anita and Joel are each given the same set of data and are asked to construct a histogram They agree to use exactly the same class intervals Anita constructs a frequency histogram and Joel constructs a relative frequency histogram TRUE or FALSE Anita s frequency histogram and Joel s relative frequency histogram will look the same except for the labeling of the vertical axis Often people invite their family friends colleagues and other associates to their birthday parties but ask that they not purchase a gift In most cases these people purchase a card but not a gift while close family members will still purchase a gift The data below reflect the amount of money spent on birthday cards and gifts for a random sample of 100 people attending birthday parties Use this boxplot to answer questions 4 through 6 x x 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 Money Spent on Cards and Gifts 4 Which of the following best describes the center of this distribution A The distribution has outliers at 24 and 40 B The range of the data is 40 0 40 C The mean of the data is 4 D The median of the data is 4 E The median of the data is 18 5 Which of the following best describes the spread of this distribution A The interquartile range of the data is 10 2 8 B The median of the data is 4 C The range of the data is 18 0 18 D The range of the data is 10 2 8 E The interquartile range of the data is 18 0 18 6 Which of the following best describes the shape of this distribution A The distribution is trimodal B The distribution has outliers at 24 and 40 C The distribution is symmetrical D The distribution is skewed to the left E The distribution is skewed to the right On February 11 2012 Joel celebrated his birthday at Bailey s Pub and Grill Below are the ages of the 11 people in attendance at the birthday meal Use this data to answer questions 7 through 11 Please write your final answer on the line before the question number You can use the calculator or you can choose to do the problems by hand in which case any work you show will be considered for partial credit 12 55 38 50 40 39 46 48 53 41 40 7 Calculate the mean of the data 8 Calculate the median of the data 9 Calculate the range of the data 10 Calculate the standard deviation of the data 11 Calculate the interquartile range of the data 13 12 To estimate the mean age of all students attending her university a statistician selected a simple random sample of 9 students Prior to going on vacation the statistician collected data for only 7 of the 9 students and determined that the median age of the 7 students was 24 years The statistician took the data with her on vacation so this median value of 24 is all you know about the ages of those 7 students You do however now know that the last two students were 18 and 36 years of age respectively Based on this information which of the following best describes the median age of all 9 students in the sample A 24 67 B 24 C 26 D 27 E Cannot be determined from the information provided On January 25 2012 Anita celebrated her birthday and on February 11 2012 Joel celebrated his birthday Both Anita and Joel went out with their family and friends to celebrate their birthdays Below are the ages of the 23 people in attendance at the two birthday meals Construct an appropriate stem and leaf plot to graphically display this data 26 46 55 30 46 50 39 46 49 34 44 51 12 55 38 50 40 39 46 48 53 41 40 14 Consider the stem and leaf plot constructed in question 13 Use the stem and leaf plot to completely describe the distribution of the ages for this sample of 23 people attending the birthday meals Test 2 Practice Test 3 Solutions 1 D A B C C 2 D Stem and leaf plots histograms and boxplots all require quantitative data 3 TRUE The two histograms will look the same see page 55 4 D The line in the box represents the median 5 A The IQR is 10 2 8 the range would be 40 0 40 6 E The outliers causes the distribution to be skewed to the right 7 Interquartile range Mean Median Range Standard deviation X x 12 55 40 462 42 n 11 11 n 1 11 1 12 6 2 2 2 Median 6th ordered observation 41 8 Median Location 9 Range Max Min 55 12 43 10 S 11 576 see page 77 for how to compute S 11 Median of the 5 smallest observations Q1 39 Median of the 5 largest observations Q3 50 IQR Q3 Q1 50 39 11 12 B With n 7 the median location n 1 2 7 1 2 4 so the 4 th ordered observation is the median 24 With the two values added n 9 so the median location 9 1 2 5 Since 18 is less than the median 24 is now the 5 th ordered observation and hence the median remains unchanged at 24 13 1 1 2 2 3 3 4 4 5 5 14 2 6 0 4 9 8 9 4 0 1 0 6 6 6 9 6 8 0 1 0 3 5 5 where 5 1 51 The distribution is skewed to the left The data ranges from 12 to 55 and the center is in the 40 s Mean 42 52 Median 46 12 would be considered an outlier

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