Question

Three coins are tossed simultaneously 200 times with the following frequencies of different outcomes.

$$\begin{array}{ccccc}\text{Outcome}& 3\text{heads}& 2\text{heads}& 1\text{heads}& 0\text{heads}\\ \text{Frequency}& 22& 76& 83& 19\end{array}$$

What is the probability of getting

(i) not more than one head?
(ii) at least two heads?
(iii) exactly two heads? [3MARKS]

Answer 1

Solution: 1 Mark each.

Number of times 0 heads or 1 head was obtained = 83 + 19 = 102
Probability of getting not more than one head = $\frac{102}{200}$ = 0.51
Number of times 2 heads or 3 heads was obtained = 76 + 22 = 98
Probability of getting at least 2 heads = $\frac{98}{200}$ = 0.49
Number of times 2 heads was obtained = 76
Probability of getting exactly 2 heads = $\frac{76}{200}$ = 0.38