Controls

Sample size

Choose how many students are in each random sample.

Generates ten independent random samples at the chosen size.
Effect size

One sample may be shifted to match the chosen effect-size band, with 50 percent probability. Because scores are bounded from 5 to 35, the actual mean shift is calibrated to land within the band.

Decision

There is a 50% chance that the research hypothesis will be true for at one of the ten samples. Otherwise, the null hypothesis is true for all ten samples. Click “Draw Samples” to proceed.

Pick the sample you think received the treatment, or choose “None of the samples”.

Sample size equals 25 and effect size is Large.

Summary

There are no samples to summarize.

The population histogram appears bell-shaped, with a slightly longer tail on the left side. The scores represent college students' overall life satisfaction (on the SWLS assessment). Each score ranges from 5 (extremely dissatisfied) to 35 (extremely satisfied). The mean for the population is 24.

Legend: Purple solid = Normal curve (μ=24, σ=6), Red dashed = Population mean (μ=24), Green solid = Sample mean (x̄).

Population (M = 24, SD = 6)

The SWLS scores are bounded at 5 and 35, and demonstrate a negative skew to the left. The X-axis ticks are at 5, 10, 15, …, 35. Bin width = 1.

Toggle the blue theoretical normal curve overlay on all charts.

Samples (10, All generated at once)

Each sample will display a histogram on the same axes as the population. Below each chart a text summary will report min, max, and mean.