A die is tossed four times. The probability of getting an odd number at least once, is

The curve $y = f(x)$ is normal probability curve, then which of the following statements are correct?

(A) mean, median and mode of the distribution coincide.

(B) the area bounded by the curve $y = f(x)$ and $x$-axis is one unit.

(C) The curve is symmetrical about the line $x = \mu$, where $\mu$ is the mean.

(D) $y$-axis is an asymptote to the curve.

Choose the correct answer from the options given below:

There are three identical boxes I, II and III, each containing two balls. In box I, both balls are red, In box II, both balls are blue and box III contains one blue ball and one red ball. A boy randomly chooses a box and takes out a ball at random from it. If the ball is red, then the probability that the other ball in the box is also red colour is:

The variance of number of heads in three tosses of a coin is :

The random variable X has the following probability distribution:

The correct value of k is:

In a game, a person is paid Rs. 2 if he gets all heads or all tails when three coins are tossed, and he will pay Rs. 2 if either one or two heads show. What can he expect to win on an average per game?

The probabilities of occurrence of two events E and F are 0.25 and 0.50 respectively. The probability of their simultaneous occurrence is 0.14. The probability that neither E nor F occurs is