00:01
Hello students, far the subpart a, they given that n is equal to 25 and x bar is equal to 19 .3, s is equal to 3 .9, then alpha is equal to 0 .05.
00:15
Now the formula for calculating the confidence interval, which is x bar plus r minus t alpha by 2 into s divided by square root of n.
00:27
Here the t alpha by 2 comma n minus 1 which is t 0 .05 by 2 .24 degrees of freedom we get 2 .064.
00:43
Now substitute the known values in the formula we get 19 .3 plus or minus 2 .064 into 3 .9 divided by square root of 25.
00:55
By simplifying this we get 19 .3 plus r minus 2 .064 into 3 .9 divided by 5.
01:07
By simplifying this we get 17 .6901 and 20 .9099.
01:16
Therefore we conclude that the 95 percentage confidence in travel for mu is 17 .6909.
01:26
901 less than new less than 20 .9099.
01:32
Then for the subpart b, they given that n is equal to 36, x bar is equal to 19 .3, s is equal to 3 .9, then alpha is equal to 0 .05...