If the sum of square of the value equals to 3390, Number of observation are 30 and Standard deviation is 7, what is the mean value of the above observation?

Option c: 8. Solution: Given: sum xi^2 = 3390, n = 30, sigma = 7 Step 1: Use variance formula. sigma^2 = sum xi^2/n - x-bar^2 49 = 3390/30 - x-bar^2 49 = 113 - x-bar^2 x-bar^2 = 113 - 49 = 64 x-bar = sqrt(64) = 8 Hence, Option C is the correct answer.

Central Tendency & DispersionMTP June 2023 Series IQuestion 3196 of 473

All Questions

If the sum of square of the value equals to $\displaystyle 3390$ , Number of observation are $\displaystyle 30$ and Standard deviation is $\displaystyle 7$ , what is the mean value of the above observation?

Options

\displaystyle 14

\displaystyle 5

\displaystyle 8

\displaystyle 11

For any discrepancies in this question, email contact@cadada.in

Correct Answer

✅ Option c — $\displaystyle 8$

All Options:

A $\displaystyle 14$
B $\displaystyle 5$
C $\displaystyle 8$
D $\displaystyle 11$

Detailed Solution & Explanation

**Given:**

\displaystyle \sum x_i^2 = 3390

\displaystyle n = 30

\displaystyle \sigma = 7

**Step 1: Use variance formula.**

\sigma^2 = \frac{\sum x_i^2}{n} - \bar{x}^2

49 = \frac{3390}{30} - \bar{x}^2

49 = 113 - \bar{x}^2

\bar{x}^2 = 113 - 49 = 64

\bar{x} = \sqrt{64} = 8

Hence, **Option C** is the correct answer.

Ready to Master Central Tendency & Dispersion?

Practice all 473 questions with instant feedback, earn XP, track your streaks, and ace your CA Foundation exam.

Start Practicing — It's Free

If the sum of square of the value equals to 3390\displaystyle 33903390, Number of observation are 30\displaystyle 3030 and Standard deviation is 7\displaystyle 77, what is the mean value of the above observation?