00:01
Okay, so i see that you need help with this question, and so i have n equals 1500, and n equals 1825, and n equals 6200.
00:13
Then we have the little n, so this is our sample 70, 90, 200, and then our standard deviation is going to be 10, 81, and 124.
00:33
And our means are 143, 230, and 58 .9.
00:47
So it wants a 95 % confidence interval, so 95 % confidence interval is 1 .96z score.
00:57
So you're going to take 143 plus or minus 1 .96 times 10 divided by first the square root of 1500.
01:09
So then that is 10 divided by the square root of 1500, and so that's 143 plus or minus 1 .96 times 0 .26.
01:33
And so that is 143 plus or minus 0 .96, and so that's 142 .04 comma, and then adding that together is 143 .96.
01:53
Then 143 plus or minus 1 .96 times 10 divided by the square root of 70.
02:01
10 divided by the square root of 70, so that's 143 plus or minus 1 .96 times 1 .1 or 1 .20.
02:19
Then i'm going to multiply that by 1 .96, and so that's 143 plus or minus 2 .343.
02:29
So 143 minus 2 .343, and that equals a confidence interval of down here, confidence interval of 140 .657 comma 145 .343.
02:57
Then next we have 143 plus or minus, oh not 143, different number now, 230 plus or minus 1 .96 times your standard deviation of 81 over the square root of 1825.
03:24
So 230 plus or minus 1 .96 times 81 divided by the square root of 1825, and then i have 1 .90 times 1 .96, and so that's 230 plus or minus 3 .716...