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Statement-1 : if the S.D. of a variable ...

Statement-1 : if the S.D. of a variable x is 6, then the S.D. of ax +b is |a| 6.
Statement-2 : The variance and S.D. is not independent of change of scale

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To solve the problem, we need to analyze the two statements provided and determine their validity. ### Step 1: Analyze Statement 1 **Statement 1**: If the standard deviation (S.D.) of a variable \( x \) is 6, then the S.D. of \( ax + b \) is \( |a| \times 6 \). **Explanation**: - The standard deviation measures the dispersion of a set of values. - When we apply a linear transformation to the variable \( x \) in the form \( ax + b \): - The constant \( b \) does not affect the standard deviation; it only shifts the data. - The coefficient \( a \) scales the data. Thus, the standard deviation of \( ax + b \) is affected by the absolute value of \( a \). Mathematically, if \( \sigma_x \) is the standard deviation of \( x \), then: \[ \sigma_{ax + b} = |a| \cdot \sigma_x \] Given that \( \sigma_x = 6 \): \[ \sigma_{ax + b} = |a| \cdot 6 \] Thus, **Statement 1 is true**. ### Step 2: Analyze Statement 2 **Statement 2**: The variance and S.D. are not independent of the change of scale. **Explanation**: - Variance is the square of the standard deviation. When we change the scale of the data (for example, multiplying by a constant \( a \)): - The variance of \( ax + b \) becomes: \[ \text{Var}(ax + b) = a^2 \cdot \text{Var}(x) \] - This shows that variance is affected by the square of the scaling factor \( a \). - Since the standard deviation is the square root of variance, it also shows dependence on the change of scale. Thus, **Statement 2 is also true**. ### Conclusion Both statements are true: - **Statement 1** is true: The S.D. of \( ax + b \) is \( |a| \times 6 \). - **Statement 2** is true: Variance and S.D. are not independent of the change of scale. ### Final Answer Both statements are true. ---
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