# 4.4 - Bootstrap Confidence Interval

Once we have a bootstrap sampling distribution there are two methods for constructing a confidence interval:

1. The standard deviation of the bootstrap distribution is the standard error which we can use to construct a bootstrap confidence interval. Recall that for a 95% confidence interval, given that the sampling distribution is approximately normal, the 95% confidence interval will be $$sample\ statistic \pm 2 (standard\ error)$$.
2. For a 95% confidence interval we can find the middle 95% bootstrap statistics. This is known as the percentile method. This is the preferred method because it works regardless of the shape of the sampling distribution.

The standard error method is covered in Section 3.3 of the Lock5 textbook and the percentile method is covered in Section 3.4.