00:01
Ok, so a population is known to have mean 45.
00:04
We want to see whether this decreases or not.
00:08
So usually a null hypothesis is that the status quo is maintained.
00:13
So the situation stays the same.
00:17
So a lot of people would actually write the null hypothesis for this to be mu equals 45.
00:24
And then the alternative hypothesis will be the contested change.
00:29
Change, so the change that someone is saying has happened.
00:35
And so in this case, that would be that there's been a decrease, so mu would be less than 45.
00:41
However, for the null hypothesis, instead of saying mu equals 45, some people say mu is greater than or equal to 45, i .e.
00:48
It's anything but what the alternative hypothesis is...