00:01
Hello students, we have given the sample size n is equal to 32 then sample mean x bar is equal to 7 .78 and sample standard deviation that is s is equal to 1 .08 and we have to test the reports claim that all the cars have the mean greenhouse gas emission of 8 tons that is we have to test the null hypothesis h0 as mu is equal to 8 versus the alternative hypothesis ha as mu is not equal to 8 and this we have to test at significance level alpha is equal to 0 .05.
00:41
Now here we have the sample size n is equal to 32.
00:44
So therefore the degrees of freedom is equal to n -1 which is equal to 31 and therefore the critical value that is tc is equal to t alpha by 2, degrees of freedom which is equal to t 0 .025, 31 and by using the t table this value is 2 .04.
01:07
Now by using the normal curve we can show the rejection region.
01:13
So here the point is critical value which is minus 2 .04 and on the right side it is positive 2 .04.
01:25
So the area to the left hand side of minus 2 .04 and the region to the right hand side of the positive 2 .04.
01:38
This is the area of the rejection.
01:41
So this is rejection region, rejection region.
01:49
Then similarly this shaded part is also the rejection region, rejection region and now in the c part we have to compute the sample test statistic and locate it in the this normal curve.
02:09
So here we have given the value of s that is the sample standard deviation and population standard deviation is unknown.
02:18
So therefore we will be using the t distribution test and the test statistic for that is given by t which is equal to x bar minus mu divided by s upon square root of n.
02:31
So therefore now this is equal to 7 .78 minus 8 divided by 1 .08 divided by square root of 32 and that is equal to minus 1 .15...