Absolute and Relative Measures of Dispersion

Q.

If $r$ is the correlation coefficient between two variables, then

1. $r\ge 1$

2. $r\le 1$

3. $\left|r\right|\le 1$

4. $\left|r\right|\ge 1$

Q.

If $r=0.2$, then the linear correlation will be necessarily

1. Perfect

2. Negative

3. Very low

4. Very high

Q.

Calculate $Q_1$ and $Q_3$ from the following data

$\begin{array}{cc}\text{Marks}& \text{Number of}\\ & \text{Students}\\ 10& 4\\ 20& 10\\ 30& 20\\ 40& 8\\ 50& 6\\ 60& 3\end{array}$

Q. $n=25,\sum x=125,\sum x^2=650,\sum y=100,\sum y^2=460,\sum xy=508$. It was observed that two pair of values of $(x,y)$ were copied as $(6,14)$ and $(8,6)$ instead of $(8,12),(6,8).$ The correct correlation coefficient is

1. $0.667$
2. $0.87$
3. $-0.25$
4. $0.356$

Q. The standard deviation of a data is $6$, when each observation is increased by $1$, then the S.D. of the new data is

1. $5$
2. $6$
3. $8$
4. $7$

Q. Which of the following are dimensionless

1. S.D.
2. M.D.
3. variance
4. coefficient of variation