00:01
Okay, so i see that you need help with these problems.
00:02
And so the first thing that i have to do in order to solve these problems is i have to calculate the t score.
00:09
So for a, the first thing that you have to do is 1 minus 0 .95, and that's 0 .05.
00:16
And then 1 minus 0 .05 divided by 2, and that's 0 .975.
00:24
And then you have 60, so your degree of freedom, you're going to subtract by 1.
00:29
So your degree of freedom is 59.
00:31
So you're going to do t, 0 .975, and your degree of freedom is 59.
00:40
So that gives you a t score of 2 .001.
00:51
So then you're ready to calculate your confidence interval.
00:57
So you're going to do 25 plus or minus 2 .001 times your standard deviation of 3 .5 divided by the square root of 60.
01:12
So then 25 plus or minus 2 .001 times 0 .4518.
01:20
And then 25 plus or minus 0 .9041.
01:27
And then your confidence interval, i'll go out four decimal places because it doesn't tell you what to round to.
01:43
So that's a.
01:48
Then for b, the same thing.
01:51
You have to calculate your t score.
01:54
So 1 minus 0 .98, which is 0 .02.
01:59
Then 1 minus 0 .02, divide that by 2.
02:03
So then that is 0 .99.
02:08
So then you have t, and then that's 0 .99.
02:14
With your degree of freedom, 75 minus 1 is 74.
02:19
So 74.
02:21
And so then your t score is 2 .3778.
02:26
So then we have 119 .6 plus or minus 2 .3778 times, and then you have your mean of, i'm sorry, your standard deviation of 23 .89 divided by the square root of 75.
02:49
So then you have 119 .6 plus or minus 6 .5594.
02:56
And then you have your confidence interval of 113 .0406 ,126 .1594.
03:11
Then c, 1 minus 0 .9 is 0 .10.
03:22
1 minus 0 .1 divided by 2...