00:01
Hello.
00:03
So this is the given information and we want to find the sample size n.
00:07
Let's look at the formula that is given by the z value at alpha over 2 divided by the margin of error or squared times the proportion into one minus the proportion.
00:31
So in this question we don't have the proportion.
00:34
So we're going to assume p to be 0 .5.
00:39
This value is a conservative p value and we use it when we don't have p.
00:47
The next thing is to find the z value so we use alpha to find that.
00:53
That's 1 minus 90 % is 0 .9 .1.
01:02
Divide this by 2 you get 0 .05.
01:08
The corresponding z value which is the critical value is 1 .645.
01:20
This we're going to have 1 .645.
01:26
The margin of error is 1 % that is 0 .01.
01:32
We're going to square that and then here we have 0 .5 into 1 minus 0 .5.
01:42
Sample size is going to be 67 64.
01:51
Now using excel we're going to type in equal to...