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TCS NQT GuideTCS NQT Numerical AbilityStandard Deviation and Variance Problems Explained

Standard Deviation and Variance Problems Explained

Learn core concepts, essential formulas, and attempt practice questions designed on the latest TCS NQT testing patterns.

Key Concepts & Formulas

  • 1Mean (mu) = Sum of items / count.
  • 2Variance (sigma^2) = Sum of (x - mu)^2 / N.
  • 3Standard Deviation (sigma) = Square root of Variance.

TCS NQT Style Practice Questions

Practice Question 1

Find the variance of data set: 2, 4, 6.

A) 2.67
B) 4
C) 1.63
D) 8

Correct Answer: A) 2.67

Step-by-step Solution: Mean = (2+4+6)/3 = 4. Squared deviations: (2-4)^2 = 4, (4-4)^2 = 0, (6-4)^2 = 4. Sum = 8. Variance = 8/3 = 2.67.

Practice Question 2

If the variance of a dataset is 16, what is the standard deviation?

A) 4
B) 8
C) 16
D) 2

Correct Answer: A) 4

Step-by-step Solution: Standard Deviation = sqrt(Variance) = sqrt(16) = 4.

Study Pro-Tip

Standard deviation is always a non-negative value.

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