Question

Based on a​ poll, 60​% of Internet users are more careful about personal information when using a public​ Wi-Fi hotspot. What is the probability that among four 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? The probability that at least one of them is careful about personal information is

Answer 1

Answer:

The probability that at least one of them is careful about personal information is 0.9744.

If the survey subjects volunteered to​ respond, then this a voluntary sampling and the estimated probability p may be biased, as only the people interested in the topic participate.

Given the subject of the survey, it is estimated that the ones who answered the survey are more careful about personal information and then the propability p is biased to a higher level than it should be if the sample was random.

Step-by-step explanation:

We can model this with a random variable, with sample size n=4 and probability of success p=0.6.

The probability that k individuals are more careful about personal information when using a public​ Wi-Fi hotspot in the sample is:

$P(x=k)=\dbinom{n}{k}p^k(1-p)^{n-k}=\dbinom{4}{k}\cdot0.6^k\cdot0.4^{4-k}$

We have to calculate the probability that 1 or more are more careful about personal information when using a public​ Wi-Fi hotspot. This can be calculated as:

$P(x\geq1)=1-P(x=0)\\\\\\P(x=0)=\dbinom{4}{0}\cdot0.6^{0}\cdot0.4^{4}=1\cdot1\cdot0.0256=0.0256\\\\\\P(x\geq1)=1-0.0256=0.9744$

The probability that 1 or more individuals in the sample are more careful about personal information when using a public​ Wi-Fi hotspot is 0.9744.