Question:

Consider the following frequency distribution: 
The mean deviation about the mean is: 

 

Show Hint

Always calculate the Mean first. If the Mean is an integer (like 9 here), the absolute deviations become very easy to calculate. If the mean is a decimal, keep at least two decimal places for accuracy.
Updated On: Apr 6, 2026
  • 4.23
  • 5.23
  • 2.32
  • 3.23
Show Solution
collegedunia
Verified By Collegedunia

The Correct Option is D

Solution and Explanation


Step 1: Understanding the Concept:

Mean deviation about the mean is the arithmetic mean of the absolute deviations of the observations from their arithmetic mean.

Step 2: Key Formula or Approach:

1. Mean ($\bar{x}$) $= \frac{\sum f_i x_i}{\sum f_i}$ 2. Mean Deviation (M.D.) $= \frac{\sum f_i |x_i - \bar{x}|}{\sum f_i}$

Step 3: Detailed Explanation:

1. Calculate $\sum f_i$: $4 + 8 + 2 + 3 + 9 = 26$. 2. Calculate $\sum f_i x_i$: $(5 \times 4) + (6 \times 8) + (8 \times 2) + (11 \times 3) + (13 \times 9) = 20 + 48 + 16 + 33 + 117 = 234$. 3. Mean $\bar{x} = 234 / 26 = 9$. 4. Calculate $\sum f_i |x_i - 9|$: $4|5-9| + 8|6-9| + 2|8-9| + 3|11-9| + 9|13-9|$ $= 4(4) + 8(3) + 2(1) + 3(2) + 9(4) = 16 + 24 + 2 + 6 + 36 = 84$. 5. M.D. $= 84 / 26 \approx 3.23$.

Step 4: Final Answer:

The mean deviation about the mean is 3.23.
Was this answer helpful?
0
0