Question

Can't find probability​

Answer 1

Answer: $0.0756,\ 0.7599$

Step-by-step explanation:

Given

Probability that a coin will land head is $0.3$ i.e. probability of success is $p=0.3$ So, the probability of failure is $q=1-0.3=0.7$

Using Binomial distribution for $n=4$

(a) Probability that the coin will lead heads exactly 3 times

$\Rightarrow P(3)=^4C_3(0.3)^3(0.7)^1\\\Rightarrow P(3)=4\times 0.7\times (0.3)^3\\\Rightarrow P(3)=0.0756$

(b)Probability that the coin lands head at least once

$\Rightarrow 1-P(0)\\\Rightarrow 1-^4C_0(0.3)^0(0.7)^4\\\Rightarrow 1-1\cdot(0.7)^4\\\Rightarrow 0.7599$