when constructing confidence intervalthere is always trade o

Solution

The advantage of a lower confidence level is that you get a narrower, more precise confidence interval. The disadvantage is that you have less confidence that the confidence interval contains the population parameter you are interested in.

So lower the confidence level only if, in your situation, the advantage of more precision is greater than the disadvantage of less confidence.

This interval contains the true population level with a high probability. This high probability is called the confidence interval.

You have two options for the confidence level: 95% or 99%. Note that is relation between the confidence level of the confidence interval and the precision of the estimate:

So you either draw a very precise conclusion with a lower level of confidence, or a less precision conclusion with a higher level of confidence.

Therefore, it is depend on you that what you are required.