Contents
Why do confidence intervals overlap?
To determine whether the difference between two means is statistically significant, analysts often compare the confidence intervals for those groups. If those intervals overlap, they conclude that the difference between groups is not statistically significant.
Should confidence intervals overlap?
The short answer is: not always. If two statistics have non-overlapping confidence intervals, they are necessarily significantly different but if they have overlapping confidence intervals, it is not necessarily true that they are not significantly different. We can illustrate this with a simple example.
What if the confidence interval contains zero?
If your confidence interval for a difference between groups includes zero, that means that if you run your experiment again you have a good chance of finding no difference between groups.
Which is the survival curve with confidence intervals?
Kaplan-Meier Survival Curve With Confidence Intervals Cumulative Incidence Curves Some investigators prefer to generate cumulative incidence curves, as opposed to survival curves which show the cumulative probabilities of experiencing the event of interest.
When do confidence intervals overlap is it statistically significant?
Determining whether confidence intervals overlap is an overly conservative approach for identifying significant differences between groups. It’s true that when confidence intervals don’t overlap, the difference between groups is statistically significant. However, when there is some overlap, the difference might still be significant.
What is the 95% confidence interval for the difference between adults and children?
Thus a 95% Confidence Interval for the differences between these two means in the population is given by Notice that this 95% confidence interval goes from 3.45 kg up to 5.35 kg. Since the interval does not contain 0, we see that the difference between the adults and children seen in this study was “significant.”
How are survival curves different from other curves?
Some studies may use a combination of different types of survival curves to express their data. The main difference between the curves is what is defined as the event or end-point. In overall survival curves, the event of interest is death from any cause.