Compute mean deviation from mean of the following distribution: Marks 10-20 20-30 30-40 40-50 50-60 60-70 70-80 80-90 No. of students 8 10 15 2 20 18 9 5

Explanation

To compute the mean deviation from the mean for the given distribution, we will follow these steps:

### Step 1: Identify the midpoints (xi) of each class interval
The midpoints are calculated as follows:
- For the interval 10-20, midpoint \( x_1 = \frac{10 + 20}{2} = 15 \)
- For the interval 20-30, midpoint \( x_2 = \frac{20 + 30}{2} = 25 \)
- For the interval 30-40, midpoint \( x_3 = \frac{30 + 40}{2} = 35 \)
- For the interval 40-50, midpoint \( x_4 = \frac{40 + 50}{2} = 45 \)
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