Skip to content
We use only essential cookies to keep you signed in and remember your preferences. See our Cookie Policy.
TestStop
MocksPracticeResourcesIndiaBlogPricing
Sign in
Questions › DSE › DSE 2008 › Q22
2 marksStatistics › Random variables and standard distributions › Expectation and varianceModerateabout 3 min

DSE 2008 Question 22: Random variables and standard distributions

The frequency distribution of variable Y, the number of heads when two damaged coins are tossed, is: F(0)=0.3F(0)=0.3F(0)=0.3, F(1)=0.45F(1)=0.45F(1)=0.45, F(2)=0.25F(2)=0.25F(2)=0.25 (these are the probabilities). To two decimal places, the mean and variance of Y (in that order) are:

Tap an option to check your answer.

Answer and worked solution

Checking your account…

Plain-text version

The frequency distribution of variable Y, the number of heads when two damaged coins are tossed, is: F(0)=0.3, F(1)=0.45, F(2)=0.25 (these are the probabilities). To two decimal places, the mean and variance of Y (in that order) are: (A) 0.95 and 0.50 (B) 0.50 and 0.95 (C) 0.95 and 0.55 (D) 0.95 and 0.45

Random variables and standard distributions has come up 173 times in 7 exams since 2005.

What this question tests

This question is on Expectation and variance, part of Random variables and standard distributions in Statistics.

The mean and spread of a random variable, and how they change under transformations and sums.

TestStop has 50 past-paper questions on this subtopic; the nearest in year are below.

  • GATE 2021 · Q40Consider that a sample of size 3 is randomly drawn from a population that takes only two values, equally…
Practise Random variables and standard distributionsMore on Expectation and variance

Similar questions from other papers

  • CUET-PG 2026 · Q35Given below are two statements: Assertion A: A random variable is a numerical description of the outcome of an experiment. Reason R: The particular numerical value of a…
  • GATE 2026 · Q41Suppose, a random variable X follows a Poisson distribution with parameter λ=25. The coefficient of variation of the distribution is (rounded off to two decimal places)
  • IIT JAM 2026 · Q42It is given that Prob(-1≤ z≤ 1)=0.683, Prob(-2≤ z≤ 2)=0.954, and Prob(-3≤ z≤ 3)=0.997, when z follows a standard normal distribution. If X follows a normal distribution…
  • CUET-PG 2025 · Q20Suppose that the random variable X takes on the values: -1, 0, and 2 with probability 1/8, 1/2 and 3/8. Find the expected value of X.
  • GATE 2025 · Q41If X is a continuous random variable whose probability density function is given by f_X(x) = { 1/x² for 1 < x < ∞; 0 elsewhere } Then the median of X is (in integer)

Question from the DSE 2008 paper. Solutions are TestStop's own. Not affiliated with or endorsed by any examination authority.