From a pack of regular playing cards, two cards are drawn at random. What is the probability that both cards will be kings, if the card is NOT replaced?

The following data about the flow of liquid was observed in a continuous chemical process plant

Mean flow rate of the liquid is

In a manufacturing plant, the probability of making a defective bolts is $$0.1$$. The mean and standard deviation of defective bolts in a total of $$900$$ bolts are respectively

Four arbitrary points $$\,\,\,\left( {{x_1},{y_1}} \right),\,\,\left( {{x_2},{y_2}} \right),\,\,\left( {{x_3},{y_3}} \right),\,\,\left( {{x_4},{y_4}} \right),\,\,\,\,$$ are given in the $$xy$$ $$-$$ plane using the method of least squares. If regression of $$y$$ upon $$x$$ gives the fitted line $$y=ax+b;$$ and regression of $$x$$ upon $$y$$ gives the fitted line $$x=cy+d,$$ then