Question

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

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

What is the probability of getting

(i) not more than 1 head?
(ii) at least two heads?
(iii) exactly two heads?

• A. 0.5, 0.3 and 0.4
• B. 0.51, 0.49 and 0.38
• C. 0.4, 0.3 and 0.2
• D. none of the above

Answer 1

The correct option is B 0.51, 0.49 and 0.38

$Probability=\frac{No.offavourableoutcomes}{Totalno.ofoutcomes}$

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