1220dea01a8576625afb83aa5da2f4cb_file-4a42dc6cd721af59012d5753a3ff41fd31d4ff5f.ipynb

confidence-intervals.ipynb

confidence-intervals

Confidence Intervals
We have developed a method for estimating a parameter by using random sampling and the bootstrap. Our method produces an interval of estimates, to account for chance variability in the random sample. By providing an interval of estimates instead of just one estimate, we give ourselves some wiggle room.
In the previous example we saw that our process of estimation produced a good interval about 95% of the time, a "good" interval being one that contains the parameter. We say that we are 95% confident that the process results in a good interval. Our interval of estimates is called a 95% confidence interval for the parameter, and 95% is called the confidence level of the interval.
The situation in the previous example was a bit unusual. Because we happened to know value of the parameter, we were able to check whether an interval was good or a dud, and this in turn helped us to see that our process of estimation captured the parameter about 95 out of every 100 times we used it.
But usually, data scientists don't know the value of the parameter. That is the reason they want to estimate it in the first place. In such situations, they provide an interval of estimates for the unknown parameter by using methods like the one we have developed. Because of statistical theory and demonstrations like the one we have seen, data scientists can be confident that their process of generating the interval results in a good interval a known percent of the time.

confidence-intervals

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