Book Online Demo

Check Your IQ

Try Test

Courses

Dropper NEET Course Dropper JEE Course Class - 12 NEET Course Class - 12 JEE Course Class - 11 NEET Course Class - 11 JEE Course Class - 10 Foundation NEET Course Class - 10 Foundation JEE Course Class - 10 CBSE Course Class - 9 Foundation NEET Course Class - 9 Foundation JEE Course Class -9 CBSE Course Class - 8 CBSE Course Class - 7 CBSE Course Class - 6 CBSE Course

Offline Centres

Q.

In an experiment with 15 observations on x, the following results were available $\sum x^{2} = 2830, \sum x = 170 .$ One observation that was 20 was found to be wrong and was replaced by the correct value 30. Then the corrected variance is

see full answer

Start JEE / NEET / Foundation preparation at rupees 99/day !!

21% of IItians & 23% of AIIMS delhi doctors are from Sri Chaitanya institute !!

An Intiative by Sri Chaitanya

a

8.33

b

78.00

c

188.66

d

177.33

answer is B.

(Unlock A.I Detailed Solution for FREE)

Ready to Test Your Skills?

Check your Performance Today with our Free Mock Test used by Toppers!

Take Free Test

Detailed Solution

$n = 15, \sum x = 170, \sum x^{2} = 2830$

One observation entered wrongly

20 instead of 30

$\sum x + 30 - 20 = 180$

New Mean $= X = \frac{180}{15} = 12$

$\sum X^{2} = \sum x^{2} + 30^{2} - 20^{2} = 3330$

Variance $= \frac{\sum X^{2}}{n} - {(X)}^{2}$

$= \frac{3330}{15} - 144 = 222 - 144 = 78$

Watch 3-min video & get full concept clarity

Related Blogs

Get ₹ 1 crore* worth scholarship for JEE / NEET / Foundation

Result Producing online coaching for JEE/NEET of south India

Largest All India Test Series for JEE/NEET

Best Books for IIT JEE

Best Books for NEET

How to Join IIT after 10th

🔥 Start Your JEE/NEET Prep at Just ₹1999 / month - Limited Offer! Check Now!

Get Expert Academic Guidance – Connect with a Counselor Today!

Related Blogs

Get ₹ 1 crore* worth scholarship for JEE / NEET / Foundation

Result Producing online coaching for JEE/NEET of south India

Largest All India Test Series for JEE/NEET

Best Books for IIT JEE

Best Books for NEET

How to Join IIT after 10th

Not sure what to do in the future? Don’t worry! We have a FREE career guidance session just for you!

In an experiment with 15 observations on x, the following results were available ∑x2=2830, ∑x=170. One observation that was 20 was found to be wrong and was replaced by the correct value 30. Then the corrected variance is