Target Exam

CUET

Subject

-- Applied Mathematics - Section B2

Chapter

Inferential Statistics

Question:

Two statements are given, one labelled Assertion (A) and the other labelled Reason (R).

Assertion (A): A simple random sample consists of five observations 2, 4, 6, 8, 10. The point estimate of population standard deviation is $\sqrt{10}$.
Reason (R): Sample standard deviation of n observations, $S =\sqrt{\frac{∑(x_i-\bar x)^2}{n}}$

Select the correct answer from the given below:

Options:

Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).

Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).

Assertion (A) is true, but Reason (R) is false.

Assertion (A) is false, but Reason (R) is true.

Correct Answer:

Assertion (A) is true, but Reason (R) is false.

Explanation:

The correct answer is Option (3) → Assertion (A) is true, but Reason (R) is false.

$\bar x=\frac{∑x_i}{n}=\frac{2+4+6+8+10}{5}=\frac{30}{5}$

$⇒\bar x=6$

Now, $∑(x_i- \bar x)^2 = (2-6)^2 + (4-6)^2 + (6-6)^2 + (8-6)^2 + (10-6)^2$

$= 16+4+0+ 4 + 16 = 40$

$∴S =\sqrt{\frac{∑(x_i-\bar x)^2}{n}}=\sqrt{\frac{40}{4}}=\sqrt{10}$

∴ Assertion is true.

Reason is false.