Question

Nts) in a certain population of voters, 72% of them plan to vote in favor of a new

Answer 1

Answer:

Probability that 10 of them plan to vote against this piece of  proposed legislation is 0.0701 or 7.01 %.

Step-by-step explanation:

Consider the event of voting against the piece as success, 'p'. So, voting in favor of the piece is failure and denoted by 'q'.

Given:

Sample size is, $n=25$

Probability of failure is, $q=72\%=0.72$

Therefore, probability of success is, $p=1-q=1-0.72=0.28$

Number of successes is, $x=10$

Now, from Bernoulli's distribution, probability of $x$ successes out of $n$ samples is given as:

$P(X=x)=_{n}^{x}\textrm{C}p^xq^{n-x}$

Here, $n=25,x=10,p=0.28,q=0.72$. Therefore,

$P(X=10)=_{25}^{10}\textrm{C}(0.28)^{10}(0.72)^{25-10}\\P(X=10)=_{25}^{10}\textrm{C}(0.28)^{10}(0.72)^{15}\\P(X=10)=3.269\times 10^{6}\times 2.962\times 10^{-6}\times 7.244\times 10^{-3}\\P(X=10)=70.142\times 10^{-3}=0.0701=7.01\%$

Therefore, probability that 10 of them plan to vote against this piece of  proposed legislation is 0.0701 or 7.01 %.