00:01
Hello, welcome to the video, and today we're going to be talking about hypothesis tests, and specifically how to determine whether or not our evidence sufficiently supports our claim.
00:11
So in this problem, we're talking about the proportion of families who own stock, and it is proposed that this proportion here, or what we're just going to call x, is equal to 48 .8%.
00:29
So we can translate this into a null hypothesis, sorry, of x equals 0 .488.
00:40
And alternatively, a broker is telling us, a broker suspects that this figure is not accurate.
00:51
It could be less or it could be greater, but they're not convinced that this is the right value.
00:56
So we can translate this into an alternative hypothesis by saying that x does not equal 0 .488.
01:05
And if we want to visualize this, let's say we have a distribution here with a peak value at the proposed 48 .8%.
01:19
And with our hypothesis test, we hope to find evidence to show that the true value of x is actually either somewhere over here, or somewhere over here, but importantly, we hope to find that it's not close to 48%.
01:37
So in other words, we're doing a two -tailed test.
01:41
We'll be testing these hypotheses at the 5 % level.
01:46
And to test these hypotheses, the broker does a survey.
01:52
He conducts a random sample of 250 families and finds that of those families, 142 of them owned some sort of stock...