Answer:
a) If we design the experiment on this way we can check if we have an improvement with the method used.
We assume that we have the same individual and we take a value before with the normal impaired condition and the final condition is the normal case.
b)
The 95% confidence interval would be given by (-1.24;-0.69)
Step-by-step explanation:
Part a
If we design the experiment on this way we can check if we have an improvement with the method used.
We assume that we have the same individual and we take a value before with the normal impaired condition and the final condition is the normal case.
Part b
For this case first we need to find the differences like this :
Normal, Xi 4.47 4.24 4.58 4.65 4.31 4.80 4.55 5.00 4.79
Impaired, Yi 5.77 5.67 5.51 5.32 5.83 5.49 5.23 5.61 5.6
Let
The second step is calculate the mean difference
The third step would be calculate the standard deviation for the differences, and we got:
The confidence interval for the mean is given by the following formula:
(1)
In order to calculate the critical value we need to find first the degrees of freedom, given by:
Since the Confidence is 0.95 or 95%, the value of and
, and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.025,8)".And we see that
Now we have everything in order to replace into formula (1):
So on this case the 95% confidence interval would be given by (-1.24;-0.69)