If the variance of a data is `121` , then the standard deviation of the data is ….. .

Options

A. `11`
B. `12`
C. `10`
D. `9`

Explanation

To find the standard deviation from the given variance, we can follow these steps:

### Step 1: Understand the relationship between variance and standard deviation.
Variance is defined as the square of the standard deviation. Mathematically, this can be expressed as:
\[ \text{Variance} = (\text{Standard Deviation})^2 \]

### Step 2: Given the variance.
In this problem, we are given that the variance of the data is \(121\).

### Step 3: Use the formula to find the standard deviation.
To find the standard deviation, we take the square root of the variance:
\[ \text{Standard Deviation} = \sqrt{\text{Variance}} \]

### Step 4: Substitute the value of variance.
Now, substituting the value of variance into the formula:
\[ \text{Standard Deviation} = \sqrt{121} \]

### Step 5: Calculate the square root.
Calculating the square root of \(121\):
\[ \text{Standard Deviation} = 11 \]

### Conclusion:
Therefore, the standard deviation of the data is \(11\).

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