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

Conclusion for a two sample t test using a P value


2m read
·Nov 10, 2024

We're told a sociologist studying fertility in Argentina and Bolivia wanted to test if there was a difference in the average number of babies women in each country have. The sociologist obtained a random sample of women from each country. Here are the results of their test.

So they take a sample of 75 women in Argentina, and these women had a mean of 2.4 babies each, with a standard deviation of 1.5. Then the standard error of the mean was 0.17. Then they calculated similar statistics for Bolivia.

Then they give us the t-test for the means being different. We were able to calculate these statistics, and they say assume that all conditions for inference have been met at the alpha equals 0.05 level of significance. Is there sufficient evidence to conclude that there is a difference in the average number of babies women in each country have?

So pause this video and see if you can answer that.

All right, now let's work through this together. So this is classic hypothesis testing right over here, where your null hypothesis is actually going to be that your means are the same—so that the mean in Argentina is equal to the mean in Bolivia.

And then your alternative hypothesis is that your means are different. What you do is you say, all right, if we assume the null hypothesis, what is the probability that we would have gotten means this far apart? That's what our p-value tells us. We have a 0.31 probability, or 31 percent probability, of getting means this far apart.

Now, if your probability, assuming the null hypothesis, is below your level of significance, your alpha right over here, then you would say all right, that seems like such a low probability. I'll reject the null hypothesis, which suggests the alternative hypothesis.

But in this situation here, if we compare our p to our alpha, we see that our p-value is for sure greater than our alpha. So in this situation, I mean, you could see it right over here: 0.31 is for sure greater than 0.05.

So in this situation, we cannot reject the null hypothesis. Cannot reject our null hypothesis, and so there is not sufficient evidence to conclude that there is a difference in the average number of babies women in each country have.

More Articles

View All
Peer Into a Fallen Battleship at Pearl Harbor | National Geographic
Here we are at the number one guns of the USS Arizona. Oftentimes diving on the USS Arizona, we come across artifacts like this shoe or boot sole. It’s artifacts like this that remind us of the human connection of the ship and those who lost their lives h…
Why Design Matters: Lessons from Stripe, Lyft and Airbnb
Today on design review, we’ll be doing something a little bit different. I’ll be interviewing Katie Dill, Stripe’s head of design. The gravitational pull is to mediocrity. It’s never easy. There is no black and white answer of like, “Oh, you ship it when …
How To Be More Likeable & Charismatic
Imagine walking into a room and feeling the atmosphere shift as all eyes turn toward you, not out of judgment, but pure interest and warmth. This isn’t a rare, unattainable skill reserved for a select few; no, it’s a powerful, accessible tool called likab…
Peter Lynch: 7 Tips to Consistently Outperform the Market
Would be terrific to know that the Dow Jones average a year for now would be X, that we’re gonna have a full-scale recession, our interest rate is gonna be 12. That’s useful stuff. You never know it though; you just don’t get to learn it. So I’ve always …
How Pitching Investors is Different Than Pitching Customers - Michael Seibel
Although I’m Michael Seibel and partner Y Combinator, today I’d like to talk about the difference between your investor pitch and your customer pitch. When most founders typically screw up here is that your customer typically knows a lot about the proble…
Doc Brown "Loved Himself Some Einstein" | StarTalk
Einstein always kind of, uh, amazes me. And it was he amazes us all, by the way. Yes, yeah, and he was just a clerk in the patent Department. Yeah, nobody knew, you know, but he’s going looking at this, and there’s a railroad station. And he spent a lot …