Question

A coin is tossed 4 times. Let E1 be the event "the first toss shows heads" and E2 the event "the second toss shows heads" and so on. That is, Ei is the event that the "i"th toss shows up heads.

A. Are the events e e and f f independent?
B. Find the probability of showing heads on both toss.

Answer 1

The events are independent.

The probability of showing heads on both toss is equal to 1/2

Explanation:

The sample space for this experiment consists of 2⁴= 16 sample points, as each toss can result in two outcomes we assume that the events are equally likely.

Two events are independent in the sample space if the probability of one event occurs, is not affected by whether the other event has or has not occurred.

In general the k events are defined to be mutually independent if and only if the probability of the intersection of any 2,3,--------, k equals the product of their respective probabilities.

P (A∩B) = P(A). P(B)

P (A∩B) = 1/2. 1/2= 1/4

Head Tail

P(E1)= 1/2 ---------- Coin 1 H,H T,H

1/4 1/4

P(E2)= 1/2 --------------- Coin 2 H, H H,T

1/4 1/4

So the events are independent.

The probability of showing heads on both toss is equal to 1/2

The sample space for this experiment consists of 2⁴= 16 sample points, out of which eight will have heads on both toss.

Or in other words ( 1/4* 1/4) = 2/4 = 1/2