Answer:
We can find the critical value 
And for this case if the confidence increase the critical value increase so then this statement is True
Step-by-step explanation:
For a confidence level given c, we can find the significance level like this:

And with the degrees of freedom given by:
We can find the critical value 
And for this case if the confidence increase the critical value increase so then this statement is True
I don’t understand your question, can you give more details please
Answer:
The ratio of the difference of the two means to Sidney's mean absolute deviation =
= 1.2195
Step-by-step explanation:
P.S - The exact question is -
Given - The means and mean absolute deviations of Sidney’s and Phil’s grades are shown in the table below.
Sidney’s Grades Phil’s Grades
Mean 82 78
Mean Absolute Deviation 3.28 3.96
To find - Which expression represents the ratio of the difference of the two means to Sidney’s mean absolute deviation?
Proof -
Given that Mean of Sidney Grades = 82
Mean of Phil's Grades = 78
So,
The difference of two means = 82 - 78 = 4
Also,
Given, Mean Absolute Deviation of Sydney = 3.28
Now,
The ratio of the difference of the two means to Sidney's mean absolute deviation =
= 1.2195
Answer:
One answer would be -2.155.