Variance and Standard Deviation

Q.

Class intervals / Frequency

15-25. 6

25-35. 11

35-45 . 7

45-55. 4

55-65. 4

65-75. 2

75-85 . 1

Q. The square root of variance gives us the value of standard deviation.

1. False
2. True

Q. If the mean value is not an integer then to find the standard deviation, it is better to use the _______ .

1. assumed mean method
2. mean method
3. step deviation method
4. direct method

Q.

Suppose population $A$ has $100$ observations $101,102,...200$ and another population $B$ has $100$ observations $151,152,...,250$. If $V_A$ and $V_B$ represents the variance of the two population respectively, then $\frac{V_A}{V_B}$ is equal to

1. $\frac{9}{4}$

2. $\frac{4}{9}$

3. $\frac{2}{3}$

4. $1$

Q. Find the value of $\sigma$ where $\sum f_i(x_i-\overline{x}{)}^2$ = 24 and N = 12.

1. 1.42
2. 1.4
3. 1.41
4. 1.44

Q. Which has more standard deviation?
Set 1 : {10, 20, 30, 40, 50} or
Set 2 : {1, 2, 3, 4, 5}

1. Set 1
2. Set 2
3. Equal

Q.

If $\sum _{i=1}^{\pi }i$ = $\frac{n(n+1)}{2}$, then $\sum _{i=1}^{\pi }(3i-2)$ =

1. 

2. 

3. 

4.