Step 1: Understanding the Concept:
There is an empirical relationship that connects the three measures of central tendency: mean, median, and mode for a moderately skewed distribution. This relationship allows us to estimate one measure if the other two are known.
Step 2: Key Formula or Approach:
The empirical formula relating mean, median, and mode is:
\[ \text{Mode} = 3 \times \text{Median} - 2 \times \text{Mean} \]
Step 3: Detailed Explanation:
We are given the following values:
Mean = 20.5
Median = 21
Substitute these values into the empirical formula to find the mode:
\[ \text{Mode} = 3 \times (21) - 2 \times (20.5) \]
\[ \text{Mode} = 63 - 41 \]
\[ \text{Mode} = 22 \]
Step 4: Final Answer:
The mode of the frequency distribution will be 22.