yego.me
💡 Stop wasting time. Read Youtube instead of watch. Download Chrome Extension

Worked example identifying sample study


2m read
·Nov 11, 2024

Let's look, let's take a look at some statistical studies and see if we can figure out what type they are. So this first one, Roy's toys received a shipment of 100,000 rubber duckies from the factory. The factory couldn't promise that all rubber duckies are in perfect form, but they promised that the percentage of defective toys won't exceed 5%. Let me underline that: they promise that the percentage of defective toys won't exceed 5%.

Roy wanted to get an estimation of the percentage of defective toys, and since he couldn't go over the hire 100,000 duckies, he took a random sample of 10 duckies. He found that 10% of them were defective. So what's going on here? Roy gets a shipment; there's 100,000 ducks in the shipment. He wants to figure out what percentage of them are defective. He can't look at all 100,000 ducks; it's not practical. So he samples 10 of them: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and he finds that one out of those 10 are defective—10% of the 10.

So first of all, this is clearly a sample study. This is a sample study. How do we know that? Well, he is taking a sample from a broader population in order to estimate a parameter. The parameter is the percentage of those 100,000 duckies that are actually defective.

Now the next question is: what kind of conclusion can you make? You know, Roy, since he got the shipment and he took a sample, and he found that 10% of the sample was defective, he might, you know, be all up in arms and say, "Oh, this toy shipment from the factory, you know, they violated this promise that the percentage of defective toys won't exceed 5% because I sampled 10 toys and 10% of those 10 toys were defective."

Well, that isn't a reasonable conclusion, because this is a small sample. This is a small sample. Think about it. If he could have sampled five duckies and if he just happened to get one of the defective ones, he would have said, "Oh, maybe 20% are defective."

What he's really got to do is sample, take a larger sample. And once again, whenever you're sampling, there's always a probability that your estimate is going to be not close or definitely not the same as the parameter for the population. But the larger your sample, the higher the probability that your estimate is close to the actual parameter for the population.

And ten, in this is just too low. In future videos, we'll talk about how you can estimate the probability or how you can figure out whether your sample seems sufficient. But for this one, for what Roy did, I don't think 10 duckies is enough. If he sampled maybe 100 duckies or more than that and he found that 10% of them were defective, well, that seems less likely to happen just purely due to chance.

Let's do a few more of these, and actually, I'll do those in the next videos.

More Articles

View All
Gordon Makes Hominy | Gordon Ramsay: Uncharted
It’s the day before the Big Cook, and I’ve got one last very important stop. On the border of the Great Smoky Mountains is the national park that is inhabited by the Cherokee Indians. I’ve heard that there is a Cherokee dish that I need to taste to believ…
Harvesting Barnacles in Portugal | Gordon Ramsay: Uncharted
[music playing] Man, those percebes were absolutely amazing. But super simple. Now according to Kiko, they’re not as simple to get. He’s arranged for me to meet a very talented local sea barnacle harvester who’ll show me how to really get these prized as…
My 3 Step Guide to Quickly Screen Stocks
Hey guys, welcome back to the channel. In this video, we’re going to be talking about a simple three-step method that I personally use in order to quickly screen stocks. So, we’re not thinking about, you know, potentially making an investment just yet. W…
The Court in Action | AP US Government and Politics | Khan Academy
Of the three branches of the US government, the judicial branch is the one that is least bound by public opinion. Supreme Court justices aren’t elected; they’re appointed, and they serve for life or until they decide to retire. Usually, justices serve on …
Every Lie You Believe In
Tim Cook of Apple, Sundar Pichai of Google, Elon Musk, Jeff Bezos, the president of the United States—when you think of the people controlling the world, these names come to mind. But the truth is, while these people have a significant influence over our …
You Can Always Leave
Imagine you have a friend called George… This story was misleading. George isn’t being threatened! He’s just being asked to pay his fair share like the rest of us. If he doesn’t like the arrangement, he can always leave. Let’s start with the question of …