Complete the variance and standard deviation of the following observations of marks of 5 students of a tutorial group: Marks out of 25:8,12,13,15,22

Explanation

To find the variance and standard deviation of the given marks of 5 students, we will follow these steps:

### Step 1: Calculate the Mean (X̄)
The mean (X̄) is calculated using the formula:
\[ X̄ = \frac{\sum X_i}{n} \]
where \(X_i\) are the observations and \(n\) is the number of observations.
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