When it is appropriate to use confidence intervals?



Ok, I have always been kind of confused by CI and p values. I understand how it makes sense to use them when we are randomly sampling from a population and want to extrapolate the CI.

What I don’t understand is if we can use it even in other use cases.
Let’s say I want to benchmark an application and measure its runtime. Let’s say I repeat this measurament 10 times and I get a certain mean and standard deviation. So far so good, now I am not sure, can I calculate a CI on this data? Like using the z-value tables I obviously get a result which looks somewhat reasonable (using something like this https://www.mathsisfun.com/data/confidence-interval-calculator.html ), but does it even make sense in this context? And if yes, what does it represent in the context of my program?

In: Mathematics

You should be using a t-distribution when you don’t know the standard deviation of the population and have to estimate it from the sample. T-distributions are wider and take into account some of the uncertainty you’re describing. However, they don’t solve all problems. For instance if the underlying distribution is sufficiently fat tailed you’ll never get a true estimate of the standard deviation because it might not exist.

You’re asking a great question but it sound like you are in an area of study where you would be well served by taking another course in statistics. A lot of science that I come across is deeply flawed because the people involved were bad at statistics.

And btw… “When is it appropriate to use confidence intervals” would make for a GREAT XKCD strip!