Welcome!

Today you'll be learning about sampling error.

In this demo, you will take the role of a scientist who has created two types of living goo balls, Pons and Beks .

There are a total of 300 Pons and 300 Beks in existence. You want to know whether Pons or Beks grow longer.

To figure out whether Pons or Beks grow longer, you'll be collecting random samples of each type of goo ball from the population. In doing so, you'll get a chance to see sampling error in action.

Spoiler Alert: There's No Difference between Pons and Beks

Typically, when we conduct studies in psychology, we don't know whether true differences exist in the population or not. That's why we collect a sample—to estimate whether difference exist in the population.

However, in this demo, you know from the get-go that there are no population-level differences between Pons and Beks in terms of length.

But try drawing samples of different sample sizes. Here are a few fun things you can explore with this demo:

• How many studies can you conduct before you run into a false positive result?
  
  
• What portion of samples show a statistically significant difference between Pons and Beks (despite no true difference existing in the population)? Why?
  
  
• Try drawing smaller and bigger sample sizes. What happens to the range of correlations in your samples, depending on sample size?
  
  
• How are your confidence intervals affected by using bigger versus smaller samples?