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Sixty-five randomly selected car salespersons were asked the number of cars they generally sell in one week. Fourteen people answered that they generally sell three cars; nineteen generally sell four cars; twelve generally sell five cars; nine generally sell six cars; eleven generally sell seven cars. Complete the table.

Data Value (# cars) Frequency Relative Frequency Cumulative Relative Frequency
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What does the frequency column in [link] sum to? Why?

65

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What does the relative frequency column in [link] sum to? Why?

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What is the difference between relative frequency and frequency for each data value in [link] ?

The relative frequency shows the proportion of data points that have each value. The frequency tells the number of data points that have each value.

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What is the difference between cumulative relative frequency and relative frequency for each data value?

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To construct the histogram for the data in [link] , determine appropriate minimum and maximum x and y values and the scaling. Sketch the histogram. Label the horizontal and vertical axes with words. Include numerical scaling.

An empty graph template for use with this question.

Answers will vary. One possible histogram is shown:

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Construct a frequency polygon for the following:

  1. Pulse Rates for Women Frequency
    60–69 12
    70–79 14
    80–89 11
    90–99 1
    100–109 1
    110–119 0
    120–129 1
  2. Actual Speed in a 30 MPH Zone Frequency
    42–45 25
    46–49 14
    50–53 7
    54–57 3
    58–61 1
  3. Tar (mg) in Nonfiltered Cigarettes Frequency
    10–13 1
    14–17 0
    18–21 15
    22–25 7
    26–29 2
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Construct a frequency polygon from the frequency distribution for the 50 highest ranked countries for depth of hunger.

Depth of Hunger Frequency
230–259 21
260–289 13
290–319 5
320–349 7
350–379 1
380–409 1
410–439 1

Find the midpoint for each class. These will be graphed on the x -axis. The frequency values will be graphed on the y -axis values.

This is a frequency polygon that matches the supplied data. The x-axis shows the depth of hunger, and the y-axis shows the frequency.
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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
Life Expectancy at Birth – Men Frequency
49–55 3
56–62 3
63–69 1
70–76 1
77–83 7
84–90 5
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Construct a times series graph for (a) the number of male births, (b) the number of female births, and (c) the total number of births.

Sex/Year 1855 1856 1857 1858 1859 1860 1861
Female 45,545 49,582 50,257 50,324 51,915 51,220 52,403
Male 47,804 52,239 53,158 53,694 54,628 54,409 54,606
Total 93,349 101,821 103,415 104,018 106,543 105,629 107,009
Sex/Year 1862 1863 1864 1865 1866 1867 1868 1869
Female 51,812 53,115 54,959 54,850 55,307 55,527 56,292 55,033
Male 55,257 56,226 57,374 58,220 58,360 58,517 59,222 58,321
Total 107,069 109,341 112,333 113,070 113,667 114,044 115,514 113,354
Sex/Year 1871 1870 1872 1871 1872 1827 1874 1875
Female 56,099 56,431 57,472 56,099 57,472 58,233 60,109 60,146
Male 60,029 58,959 61,293 60,029 61,293 61,467 63,602 63,432
Total 116,128 115,390 118,765 116,128 118,765 119,700 123,711 123,578
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The following data sets list full time police per 100,000 citizens along with homicides per 100,000 citizens for the city of Detroit, Michigan during the period from 1961 to 1973.

Year 1961 1962 1963 1964 1965 1966 1967
Police 260.35 269.8 272.04 272.96 272.51 261.34 268.89
Homicides 8.6 8.9 8.52 8.89 13.07 14.57 21.36
Year 1968 1969 1970 1971 1972 1973
Police 295.99 319.87 341.43 356.59 376.69 390.19
Homicides 28.03 31.49 37.39 46.26 47.24 52.33
  1. Construct a double time series graph using a common x -axis for both sets of data.
  2. Which variable increased the fastest? Explain.
  3. Did Detroit’s increase in police officers have an impact on the murder rate? Explain.
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Source:  OpenStax, Introductory statistics. OpenStax CNX. May 06, 2016 Download for free at http://legacy.cnx.org/content/col11562/1.18
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