Q. 75.0( 3 Votes )

# If a variable X takes values 0, 1, 2, ….., n with frequencies ^{n}C_{0}, ^{n}C_{1}, ^{n}C_{2}, …….^{n}C_{n}, then write variance X.

Answer :

we know, mean x =

**Hence,**

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The sum and the sum of squares of length x (in cm) and weight y (in g) of 50 plant products are given below:

Which is more variable, the length or weight?

RS Aggarwal - Mathematics

If x_{1}, x_{2}, ……, x_{n} are n values of a variable X and y_{1}, y_{2}, ……., y_{n} are n values of variable Y such that y_{i} = ax_{i} + b, i = 1,2, ……, n, then write Var(Y) in terms of Var(X).

The mean and variance of the heights and weights of the students of a class are given below:

Which shows more variability, heights or weights?

RS Aggarwal - Mathematics

If the sum of the squares of deviations for 10 observations taken from their mean is 2.5, then write the value of standard deviation.

RD Sharma - MathematicsThe mean and standard deviation of 18 observations are found to be 7 and 4 respectively. On rechecking it was found that an observation 12 was misread as 21. Calculate the correct mean and standard deviation.

RS Aggarwal - MathematicsFollowing are the marks obtained, out of 100, by two students Ravi and Hashina in 10 tests:

Who is more intelligent and who is more consistent?

RD Sharma - Mathematics