Answer:
We have to find the 90% confidence interval for the mean
Given sample size
Sample mean
Population standard deviation
Here the confidence level is 90% then
And
The 90% confidence interval is
Here is the critical value at 0.05
From the tables
Now the 90% confidence interval is =
=
=(3840.44, 4133.56)
Hence the 90% confidence interval for the mean is (3840.44, 4133.56)
The graph is stretch/shrunk by a factor of a. The Domain is h=
Answer: 
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Explanation:
Point-slope form is

where m is the slope and
is the point the line goes through.
We're given the slope of m = 5/6, and we want the line going through (-8,0) which is the x-intercept -8. The x-intercept always occurs when y = 0.
So,

We can replace the y-0 with y; however, I'm going to keep that 0 so that the equation better matches the point-slope form.