Variance and Standard Deviation

Q. If $\overline{X}$ is the mean of a set of N observations, then

$\frac{\sum (X-\overline{X}{)}^2}{N}=?$

1. Standard deviation
2. Root mean square deviation
3. Mean Deviation
4. Variance

Q. Which of the following does not have the same unit as that of the data?

1. Variance
2. Inter-quartile range
3. Mean Deviation
4. Standard deviation

Q.

The means of five observations is 4 and their variance is 5.2. If three of these observations are 1, 2, and 6, then the other two are:

1. 4 and 7
2. 5 and 6
3. 2 and 9
4. 3 and 8

Q. The square root of ___ is called standard deviation

Q.

The distance travelled by a scooter during five months are respectively 890 km, 940 km, 640 km, 570 km and 760 km. Find the standard deviation of the distances.

1. 141.3 km

2. 160.5 km

3. 180.7 km

4. 192.8 km

Q.

If the S.D of a set of observations is 4 and if each observation is divided by 4, the S.D of the new set of observations will be

1. 4
2. 2
3. 3
4. 1

Q. If $\overline{X}$ is the mean of a set of N observations, then $\frac{{\sum }^{}(X-\overline{X}{)}^2}{N}$= .

1. standard deviation
2. mean deviation
3. root mean deviation
4. variance

Q. does not have the same unit as that of the data.

1. Mean deviation
2. Standard deviation
3. Inter-quartile range
4. Variation

Q.

Standard deviation about mean $\left(\overline{x}\right)$ for a given discrete frequency distribution $x_1,x_2,x_3,.....x_n$ with frequencies $f_1,f_2,f_3,...f_n$ is

1. 
   

2. 

3. 
   

4. 
   

Q. The electricity consumption (in units) of a household for 6 months are 94, 96, 104, 111, 108 and 102. Calculate standard deviation using the assumed mean method.

1. 5.2
2. 6.04
3. 7.12
4. 4.06