Find the mean deviation about the mean for the data :
`{("Height",,95-105,105-115,115-125,125-135,135-145,145-155,"in cms"),("Number of Boys" ,,9,13,26,30,12,10,):}`

Explanation

To find the mean deviation about the mean for the given data, we will follow these steps:

### Step 1: Organize the Data
We have the following data:
- Height intervals: 95-105, 105-115, 115-125, 125-135, 135-145, 145-155
- Number of Boys (frequency): 9, 13, 26, 30, 12, 10

### Step 2: Calculate the Midpoint (XI) for Each Class Interval
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