Answer: 
Step-by-step explanation:
As per given , we have
n = 11

Since population standard deviation is missing, so we use t-test.
Critical t-value for 99% confidence :
[using two-tailed t-value table]
Confidence interval :

Hence, 99% confidence interval for the mean amount of time that students spend in the shower each day.= 
$6.
You can get this by dividing the original number by 3 and then the new answer by 2.
Explanation:
All values in the x-column get filled with -2.
The graph is the vertical line, x = -2.
__
You are told x=-2. There is nothing to figure out. The value of y is irrelevant.
That equation describes a vertical line. The points on the line have x-coordinate -2, and any (every) y-coordinate.
Slope= -5/3 when using y^2-y^1 divided by x^2-x^1