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Inferential Statistics

Practice

  1. Use the two frequency tables to compare the life expectancy of men and women from 20 randomly selected countries. Include an overlayed frequency polygon and discuss the shapes of the distributions, the center, the spread, and any outliers. What can we conclude about the life expectancy of women compared to men?
Life expectancy at birth – women Frequency
49–55 3
56–62 3
63–69 1
70–76 3
77–83 8
84–90 2
Table 2.44

Life expectancy at birth – men Frequency
49–55 3
56–62 3
63–69 1
70–76 1
77–83 7
84–90 5

Table 2.45

  1. Listed are 29 ages for Academy Award winning best actors in order from smallest to largest.

18; 21; 22; 25; 26; 27; 29; 30; 31; 33; 36; 37; 41; 42; 47; 52; 55; 57; 58; 62; 64; 67; 69; 71; 72; 73; 74; 76; 77

  1. Find the 40th percentile.
  2. Find the 78th percentile.
  1. Find the mean for the following frequency tables.
  1. Grade Frequency
    49.5–59.5 2
    59.5–69.5 3
    69.5–79.5 8
    79.5–89.5 12
    89.5–99.5 5
    Table 2.51
  2. Daily low temperature Frequency
    49.5–59.5 53
    59.5–69.5 32
    69.5–79.5 15
    79.5–89.5 1
    89.5–99.5 0
    Table 2.52
  3. Points per game Frequency
    49.5–59.5 14
    59.5–69.5 32
    69.5–79.5 15
    79.5–89.5 23
    89.5–99.5 2
    Table 2.53

Use the following information to answer the next two exercises: The following data are the distances between 20 retail stores and a large distribution center. The distances are in miles.

29; 37; 38; 40; 58; 67; 68; 69; 76; 86; 87; 95; 96; 96; 99; 106; 112; 127; 145; 150

  1. Use a graphing calculator or computer to find the standard deviation and round to the nearest tenth.
  2. Find the value that is one standard deviation below the mean.