Frequency Distribution

Step 5: Determine Relative Frequencies

Relative frequency is the proportion of a sample that belongs to a particular class. We calculate the relative frequency by dividing the class frequency by the total number of data points, n. The sum of the relative frequencies should be one, but due to rounding errors, sometimes it is not exactly one.

    Table IV
    Actual and Relative Frequency of Serum Glucose Levels in 130 Hospital Employees
    Intervals (mg/dL) Tally Frequency Relative Frequency
    65 - 70 \\ 2 0.015
    70 - 75 \\\\ \\ 7 0.054
    75 - 80 \\\\ \\\\ \ 16 0.123
    80 - 85 \\\\ \\\\ \\\\ \\\\ \\\\ \\\\ \ 31 0.238
    85 - 90 \\\\ \\\\ \\\\ \\\\ \\\\ 24 0.185
    90 - 95 \\\\ \\\\ \\\\ \\\ 18 0.138
    95 - 100 \\\\ \\\\ \\\ 13 0.100
    100 - 105 \\\\ \\\\ 10 0.077
    105 - 110 \\\\ 5 0.038
    110 - 115 \\\\ 4 0.031
    Total n = 130 0.999

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