Link: Stats
What is confidence intervals?
A value to quantify the confidence level in the estimated parameters.
95% confidence intervals in Bootstrapping: is an interval that covers 95% of the means.
Why are confidence intervals useful?
Anything outside of confidence interval is less than 5%. So the P-value of anything outside of confidence interval is <0.05.
Use confidence intervals to compare two samples

When the 95% CI do not overlap, we can say there is a statistically significant difference in the weight of femal and male mice, aka we know the p-vale is < 0.05.