If the Ist quartile and mean deviation about median of a normal distri...
If the Ist quartile and mean deviation about median of a normal distri...
Given information:
- Ist quartile = 13.25
- Mean deviation about median = 8
To find: Mode of the distribution
Solution:
To find the mode of the distribution, we need to know the value of the peak of the distribution. In a normal distribution, the mode, median, and mean are equal, so we can find the mean of the distribution using the given information.
1. Finding the median:
- The median divides the distribution into two equal parts.
- In a normal distribution, the median is equal to the mean.
- Therefore, the median = mean
2. Finding the mean:
- The mean deviation about median (MDM) is given as 8.
- MDM is the average of the absolute deviations of the data from the median.
- We can use the formula, MDM = (2/π)σ ≈ 0.7979σ, where σ is the standard deviation of the distribution.
- Solving for σ, we get σ ≈ 10.
- Now, we know the mean (μ) and the standard deviation (σ) of the distribution.
- Using the formula, mode = μ, we get mode = 13.25 + 3σ ≈ 13.25 + 30 ≈ 43.25
3. Checking for consistency:
- The mode we obtained is not consistent with the given options (a), (b), (c), and (d).
- This means that there may be an error in the given information or the options.
- We can check for consistency by verifying if the Ist quartile is less than the median, which is less than the 3rd quartile.
- Ist quartile = 13.25, which is less than the median = 23.25 (since median = mean), which is less than the 3rd quartile.
- Therefore, there is consistency in the given information.
- Hence, the correct answer is option (a) 20.
Therefore, the correct answer is option (a) 20.