Question

It is estimated that 4000 of the 10,000 voting residents of a town are against a new sales tax. If 15 eligible voters are selected at random and asked their opinion, what is the probability that at most 7 favor the new tax?

Answer 1

The probability that at most 7 favor the new tax is 0.7869

Explanation:

Total number of voting resident = 10000

number of voting resident against new sales tax = 4000

therefore probability of choosing a voting resident against new sales tax = 4000/10000 = 0.4

If 15 eligible voters are selected at random and asked their opinion, what is the probability that at most 7 favor the new tax

Using binomial,

number of selected voters(n) =15,

p=0.4

P(x<=0.7) = binomialcdf(15, 0.4, 7)

Using your calculator

P(x<=0.7) = binomialcdf(15, 0.4, 7) = 0.7869