Ask a Doubt
Request a call back

Join NOW to get access to exclusive study material for best results

CBSE Class 12-science Answered

A box contains 16 bulbs , out of which 4 bulbs are defective. Three bulbs are drawn at random from the box. Let X be the no of defective bulbs drawn . find the mean and variance of X
Asked by haroonrashidgkp | 05 Nov, 2018, 09:42: PM
answered-by-expert Expert Answer
Let X be the random variable represents number of defective bulbs drawn.
X can take values from 0 to 3
begin mathsize 16px style straight P left parenthesis straight X equals 0 right parenthesis equals fraction numerator straight C presuperscript 12 subscript 3 over denominator straight C presuperscript 16 subscript 3 end fraction space equals space 11 over 28 space space space space space space space space space space space space defective space bulbs space equals space 4 space and space non minus defective space bulbs space equals space 16 minus 4 equals 12 straight P left parenthesis straight X equals 1 right parenthesis equals fraction numerator straight C presuperscript 4 subscript 1 straight C presuperscript 12 subscript 2 over denominator straight C presuperscript 16 subscript 3 end fraction space equals space 33 over 70 straight P left parenthesis straight X equals 2 right parenthesis equals fraction numerator straight C presuperscript 4 subscript 2 straight C presuperscript 12 subscript 1 over denominator straight C presuperscript 16 subscript 3 end fraction space equals 9 over 70 Find space mean space and space variance. end style
Answered by Sneha shidid | 08 Nov, 2018, 12:17: PM

Concept Videos

Multiple Choice Questions Practice Test
Answered Unanswered My Questions My Answers
CBSE 12-science - Maths
there are 4 cards numbered 1 to 4 one number on one card . 2 cards are drawn at random without replacement . let x denote the sum of numbers on the 2 drawn cards . find the mean and varience of x  
Asked by alanpeter9611 | 12 Feb, 2019, 05:18: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Maths
Four bad eggs are mixed with 10 good ones . three eggs are drawn one by one without replacement. Let X be the no of bad eggs  drawn . Find the mean and variance of X.  
Asked by haroonrashidgkp | 07 Nov, 2018, 09:14: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Maths
A box contains 16 bulbs , out of which 4 bulbs are defective. Three bulbs are drawn at random from the box. Let X be the no of defective bulbs drawn . find the mean and variance of X
Asked by haroonrashidgkp | 05 Nov, 2018, 09:42: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Maths
What is the mean of a random variable
Asked by Topperlearning User | 04 Jun, 2014, 01:23: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Maths
Define variance and standard deviation of a random variable.
Asked by Topperlearning User | 04 Jun, 2014, 01:23: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Maths
Find the mean of the number obtained on a throw of an unbiased dice
Asked by Topperlearning User | 04 Jun, 2014, 01:23: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Maths
Two dice are thrown simultaneously. If X denotes the number of sixes, find the variance of X.
Asked by Topperlearning User | 04 Jun, 2014, 01:23: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Maths
In a meeting, 70% of the members favour and 30% oppose a certain proposal. A member is selected at random and we take X = 0 if he opposed, and X = 1 if he is in favour. Find E(X) and Var(X).
Asked by Topperlearning User | 04 Jun, 2014, 01:23: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Maths
Let a pair of dice be thrown and the random variable X be the sum of the numbers that appear on the two dice. Find the mean or expectation of X.
Asked by Topperlearning User | 04 Jun, 2014, 01:23: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Maths
A bag contains 4 black and 3 red balls. Let X be the random variable of red balls. Find the mean and variance of the random variable X, if three balls drawn successfully with replacement.
Asked by Topperlearning User | 04 Jun, 2014, 01:23: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
My Class Videos Tests ₹ Plans Ask a Doubt
Get Latest Study Material for Academic year 24-25 Click here
×