00:01
In question 83, we are given that the proportion of births in china that are girls is 46 .7%, but that we also don't believe this figure and are conducting our own study.
00:12
So the no hypothesis here is that the proportion is equal to 0 .467, and the alternative hypothesis is that it is not equal to 0 .467.
00:31
So this is a two -tailed test.
00:33
And we've also taken a random sample of 150 births, 60 of which were female.
00:47
So we can calculate a sample proportion.
00:56
That comes out to 40%.
00:59
And so to test our claim that the proportion is not equal to 0 .467, we can assume a significance level of 0 .05.
01:09
And then go ahead and calculate our test statistic.
01:13
So sample proportions are approximately normally distributed.
01:20
So the test statistic is z and it is equal to you.
01:39
And so if you want to see my detailed calculation, this is minus 1 .645 in case you can't see that...