00:01
A poll of 168 adult americans reveals that 48 of them, or 48 % of them, surveyed prefer the democratic candidate for the presidency.
00:13
At the 5 % level of significance test the claim that at least half of all voters prefer the democrat.
00:21
So here we have a p hat of 0 .48 and a p of 0 .5, alpha is 0 .05.
00:34
And what we're testing here, the null hypothesis is that p is greater than or equal to .50.
00:40
The alternative is that p is less than .50.
00:45
So our critical value is negative 1 .645, and our test statistic is 0 .48 minus 0 .50 divided by the square root of 0 .50 times 0 .50, divided by 1068, and that's a test statistic of negative 1 .303.
01:05
So we would fail to reject the null hypothesis for number three.
01:18
In number four, according to a recent poll, 50 % of americans would vote for the incumbent president if a random sample of 100 people results in a proportion of 45%...