Okay kiddo, so let's say we have a bunch of numbers, like 1, 2, 3, 4, 10. These numbers are kind of like your toys - some numbers might be small and some might be big, but they're all important!
Now, sometimes we might find a number that seems to be really different from the others. This is kind of like when one of your toys is broken or missing, and it stands out from the rest. In statistics, we call this an outlier.
To figure out if a number is an outlier or not, we can use something called Grubb's test. This is like a tool that helps us decide if a number is too big or too small compared to the others.
We use Grubb's test by comparing the outlier to the other numbers, kind of like comparing your broken toy to your other toys. If the outlier is really different from the others, then we say it's a true outlier. But if it's not really that different, then it might just be a mistake or a fluke - like when you accidentally drop a toy and it looks different even though it's still okay.
So Grubb's test is like a way to make sure we're not throwing away important information (like a really big number that actually is important) or keeping information that doesn't belong (like an accidental error or a toy that doesn't fit in with the rest). It helps us make sure our data is accurate and reliable, like how you make sure all your toys are clean and working properly.