Marks obtained by 4 students are : 25, 35, 45, 55. The average deviation from the mean is
Explanation
Step 1: Calculate the Mean (xˉ)
The mean is the sum of all observations divided by the total number of observations (n=4):
Step 2: Calculate the Absolute Deviations from the Mean
We find the distance of each mark from the mean (40) by taking the absolute value ∣xi−xˉ∣:
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For 25: ∣25−40∣=∣−15∣=15
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For 35: ∣35−40∣=∣−5∣=5
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For 45: ∣45−40∣=∣5∣=5
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For 55: ∣55−40∣=∣15∣=15
Step 3: Calculate the Average Deviation (MD)
The average deviation is the sum of these absolute deviations divided by the number of students:
Final Answer
The average deviation from the mean is 10.