Past Paper question on AQA S1 Jan 2010

Can some one explain the reasoning behind the answer to question 5 part c on this paper?

Need link to the paper.

Well, what's the whole point of a 98% confidence interval for $\mu$? It means it's an interval that has a 98% chance of containing $\mu$. So what is the chance that it does not contain $\mu$?

2% I get it.
So what exactly is a confidence interval?
Is it a range where the mean of a population could be found in and it is made using a samples: size, mean and standard deviation.

A n% confidence interval is an interval with which the population mean has a n% probability of being in it.

Ok thanks. Another question, so how do you did whether two events are mutually exclusive or not and whether they are independent or not?
For mutually exclusive do you find the probability of both events occurring and if equals 0 then they are?
For independent events do you find the probability of A given B occurs and A given B' and if equal they are independent?
Thanks in advance.