Q3.

If for a group of 20 items, ∑x = 1452, ∑x² = 144280 and mode = 63.7, then Pearsonian coefficient of skewness is equal to:

Q4.

For a group of 50 male workers, the mean and the standard deviation of their daily wages are ₹63 and ₹9, respectively. For a group of 40 female workers, these values are ₹54 and ₹6, respectively. What is the standard deviation of the combined group of these 90 workers?

Q5.

Let the joint probability density function of \( (X, Y) \) be

\[f(x, y) = \begin{cases} 6xy^2 & \text{if } 0 < x < 1, 0 < y < 1 \\ 0, & \text{otherwise} \end{cases}\]

Then \( P\left(\frac{1}{2} < X < \frac{3}{4}\right) \) is: