Frequencies Information and Courses from MediaLab, Inc.
These are the MediaLab courses that cover Frequencies and links to relevant pages within the course.
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| Using Frequency Distributions A frequency distribution is a chart that groups data into different classes, and then graphically shows how many data points fall into each class. A frequency distribution allows the reader to see easily the approximate center and spread of the data. Table II shows the frequencies of different hemoglobin concentrations. Figure 2 is a histogram of the data. Table II Frequency distribution of blood hemoglobin levels from healthy women determined on the Coulter Gen S Hemoglobin (gm/dL) Number of Women 6 - 8 1 8 - 10 2 10 - 12 10 12 - 14 25 14 - 16 9 16 - 18 1 Figure 2 Frequency Distribution Blood Hemoglobin Levels from 48 Healthy Women Determined on the Coulter Gen S | View Page |
| Step 4: Determine Frequencies Now we calculate the frequencies of each class by adding the number of tallies in each. Note that the sum of all class frequencies equals the total number of observations in the sample. Intervals Tally Frequency 65 - 70 \\ 2 70 - 75 \\\\ \\ 7 75 - 80 \\\\ \\\\ \ 16 80 - 85 \\\\ \\\\ \\\\ \\\\ \\\\ \\\\ \ 31 85 - 90 \\\\ \\\\ \\\\ \\\\ \\\\ 24 90 - 95 \\\\ \\\\ \\\\ \\\ 18 95 - 100 \\\\ \\\\ \\\ 13 100 - 105 \\\\ \\\\ 10 105 - 110 \\\\ 5 110 - 115 \\\\ 4 Total n = 130 | View Page |
| 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 | View Page |