List of practice Questions

The mean of 12 observations was calculated as 28. Later, it was found that one observation was wrongly recorded as 46 instead of 26, and another observation was completely omitted. If the correct mean is 27, find the value of the omitted observation.

When two coins are tossed, what is the probability of at most two heads?

Two cards are drawn at random and without replacement from a pack of 52 playing cards. Find the probability that both the cards are black.

If A + B are independent events, P(A \cup B) is equal to

The median of the given data is
89, 45, 56, 67, 89, 45, 78, 45, 78, 45, 67

The average of the squares of the first 50 natural numbers is