Confidence Intervals

Question 1

What if you do not know a population mean?

Answer 1

You can give estimates within a particular degree of accuracy, we can give a minimum and maximum value and state how confident we are that the real mean will sit between these two values.

Question 2

What is a confidence interval? And how accurate do we have to be?

Answer 2

The range of possibilities for a population mean are called confidence intervals and can be to various degrees of accuracy.
The bigger percentage the wider the gap between min and max value.