For the given distinct values $x_{1}, x_{2}, x_{3}, . . . . . x_{n}$ occurring with frequencies $f_{1}, f_{2}, f_{3}, . . . f_{n}$ respectively. The mean deviation about mean where $¯ x$ is the mean and N is total number of observations would be

Q. IF

x_{1}, x_{2}, . . . . x_{n}

are

n

observations such that

\sum_{i = 1}^{n} x_{i}^{2} = 400

and

\sum_{i = 1}^{n} x_{i} = 80

then the least value of

n

Q. Given n observations x₁, x₂ ......x_n and their central tendency a, the mean deviation about a, M.D(a) =

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Let x1,x2,.....xn be n observations and ¯¯¯¯¯X be their arithmetic mean. The formula for the standard deviation is given by

The correct option is C √1n∑ni=1(xi−¯¯¯¯¯X)2It is a fundamental concept that, Standard deviation of n observation x1,x2,...........xn is given by formula,σ= ⎷1nn∑i=1(xi−¯X)2

Let $x_{1}, x_{2}, . . . . . x_{n}$ be $n$ observations and $¯ ¯¯¯ ¯ X$ be their arithmetic mean. The formula for the standard deviation is given by

The correct option is C $\sqrt{\frac{1}{n} \sum_{i = 1}^{n} {{(x}_{i} - ¯ ¯¯¯ ¯ X)}^{2}}$
It is a fundamental concept that,
Standard deviation of $n$ observation $x_{1}, x_{2}, . . . . . . . . . . . x_{n}$ is given by formula,
$σ = \sqrt{\frac{1}{n} n \sum i = 1 {{(x}_{i} - ¯ X)}^{2}}$