Question

Based on a​ poll,

69%

of Internet users are more careful about personal information when using a public​ Wi-Fi hotspot. What is the probability that among

three randomly selected Internet​ users, at least one is more careful about personal information when using a public​ Wi-Fi hotspot? How is the result affected by the additional information that the survey subjects volunteered to​ respond?

Answer 1

Solution:

Given: Based on a​ poll, 69% of Internet users are more careful about personal information when using a public​ Wi-Fi hotspot.

That is: p = 0.69

then q = 1- p = 1 - 0.69 = 0.31

n = sample size = 3

We have to find:

P( At least one internet users is more more careful about personal information when using a public​ Wi-Fi hotspot ) =........?

That is:

Here X = Number of internet users is more more careful about personal information when using a public​ Wi-Fi hotspot follows a binomial probability distribution with n = 3 and p = 0.69

Thus

Binomial probability formula:

where

thus

Thus

How is the result affected by the additional information that the survey subjects volunteered to​ respond?

It is very possible that the result is not valid because the sample may not be representative of the people who use public​ Wi-Fi.