00:01
Okay, so i see that you need help with this problem and it says if n equals 300 and the probability is 0 .22, find the margin of error at a 99 % confidence interval.
00:14
And so that would be a z -score of 2 .576.
00:19
So you're going to take 0 .22 plus or minus 2 .576 times the square root of 0 .22 times 0 .78 and that's over 300.
00:35
And so you're going to take 0 .22 times 0 .78 and we're going to be dividing that by 300.
00:46
And so that's 0 .22 plus or minus 2 .576 times the square root of 0 .000572.
00:58
And so i have the square root of 0 .000572 and i'm going to then multiply that by 2 .576.
01:14
And so i have 0 .22 plus or minus 0 .61, 0 .062 and 0 .22 minus 0 .062 and that's 0 .158 comma.
01:34
And then adding that together would be 0 .282.
01:42
Then, so that's for number one.
01:44
Then number two, out of 500 people sampled, 325 out of the five had kids.
01:55
Based upon this, construct a 99 % confidence interval.
01:58
Give your answer as decimals to three places.
02:02
So out of 500 people, so that's 325 divided by 500.
02:08
That is equal to 0 .65.
02:11
So then you have plus or minus for 99 % confidence interval, that's 2 .576 times the square root of 0 .65 times 0 .35.
02:24
Then that is divided by 500.
02:28
So 0 .65 times 0 .35.
02:32
Then that's divided by 500.
02:35
And so then i have 0 .65 plus or minus 2 .576 times the square root of 0 .00400455.
02:50
So then we have the square root of point and then three zeros, 455.
02:57
And then that's multiplied by 2 .576.
03:02
And so then i have 0 .65 plus or minus 0 .055.
03:11
0 .65 minus 0 .055.
03:14
And so that's 0 .595 comma.
03:20
And then adding that 0 .705...