This article covers frequently-asked questions about Amplitude's Experiment Results chart.

## Questions

- Why is my graph displaying an error state?
- Why is reaching significance taking longer than it should?

## Answers

### Why is my graph displaying an error state?

A common mistake is to attempt to generate a chart using only one variant.

The Experiment Results chart needs something to compare your control to in order to generate results. If you neglect to include **both** the control and **at least one** variant, your chart will not display anything.

### Why is reaching significance taking longer than it should?

When using a T-test, be sure to plug in the number of samples per variant before launching the experiment. You can get this information from the duration estimator. With a T-test, you will have to wait until your experiment reaches the specified sample size before Experiment Results will run the p value and confidence interval computations.

With sequential testing, even with a large MDE, it can take some time to reach statistical significance if your experiment’s lift is small. A T-test will generally require fewer samples to detect the same lift.