Overview
This lecture explains how to construct a frequency table using quantitative data about the number of cars owned by 25 families, covering all key columns and their calculations.
Steps to Create a Frequency Table
- List all possible data values (x) in order, representing the number of cars (0, 1, 2, 3, 4).
- The first column (x) contains the data values (quantitative data).
- The second column is absolute frequency (F), showing how many times each data value appears.
- Count each data value: 0 cars (4), 1 car (12), 2 cars (4), 3 cars (3), 4 cars (2).
- The sum of all frequencies (F) must equal the total number of data points (N=25).
- The next column is cumulative frequency (F_accumulated), which adds up frequencies as you move down: 4, 16, 20, 23, 25.
- The lowercase h column (relative frequency) is calculated as F/N for each data value.
- Use a calculator to get decimal values for each h.
- The percentage column (optional) is each h value multiplied by 100.
- The sum of all h values should be approximately 1, and the sum of percentages should be 100%.
- The cumulative h (relative frequency accumulated) column adds up h values down the table, ending with 1.
Key Terms & Definitions
- Absolute Frequency (F) — Number of times a data value appears in the dataset.
- Cumulative Frequency (F_accumulated) — Running total of frequencies up to a certain data value.
- Relative Frequency (h) — Absolute frequency divided by the total number of data points (F/N).
- Relative Frequency Accumulated — Running total of relative frequencies.
- Total Number (N) — Total data points in the sample, here N=25.
Action Items / Next Steps
- Practice creating a frequency table with similar data.
- Watch upcoming videos for explanations of statistical parameters.