Question 41

Mathematics Statistics Easy

If the standard deviation of ( x, y ) and ( z ) is ( p ) , then the standard deviation of ( 3x+5,3y+5,3z+5 ) is

(A) ( 3p+5 )
(B) ( 3p )
(C) ( p+5 )
(D) ( 9p+15 )
✓ Correct Answer: Option B Verified Solution

📘 Step-by-Step Solution & Detailed Explanation:

If the standard deviation of (x), (y), and (z) is (p), then the standard deviation of (3x + 5), (3y + 5), (3z + 5) is: \[\] The standard deviation measures variability, and it is only affected by scaling (multiplication) but not by adding a constant. The general rule is: \[\] - Scaling a variable by a constant (a) scales the standard deviation by ( |a| ). \[\] Adding a constant to all data points does not affect the standard deviation. \[\] Here, the transformation is (3x + 5), (3y + 5), (3z + 5). The scaling factor is (3). \[\] Therefore, the new standard deviation becomes: |3| \(\times\) p = 3p \[\] \[\] \[\] Correct Answer: (b)

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