Mr. Good Wrench advertises that a customer will have to wait no more than 30 minutes for an oil change. A sample of 26 oil changes had a standard deviation of 4.8 minutes. Use this information to calculate a 90% confidence interval for the population standard deviation waiting time for an oil change.

The 90% confidence interval for the population standard deviation waiting time for an oil change is (3.9, 6.3).

Step-by-step explanation:

The (1 - α)% confidence interval for the population standard deviation is:

The information provided is:

n = 26

s = 4.8 minutes

Confidence level = 90%

Compute the critical values of Chi-square as follows:

*Use a Chi-square table.

Compute the 90% confidence interval for the population standard deviation waiting time for an oil change as follows:

Thus, the 90% confidence interval for the population standard deviation waiting time for an oil change is (3.9, 6.3).

Step-by-step explanation:

No, unless the function decides to follow a different pattern. See more explanation below.

Step-by-step explanation:

He is wrong, the table doesn't tell us what happens at x=6.

It does tell us the following:

1) When x=-4, f(x)=6.

2) When x=-2, f(x)=3.

3) When x=0, f(x)=-1.

4) When x=2, f(x)=-4.

So maybe he got it the x and f(x) value switched in his brain.

Because according to 1) x=-4 when f(x)=6.

If the points keep having x increase while y decreases, then every x>2 will have a y less than -4 correspond to it.