Answer:
a) 
b)
c)
Step-by-step explanation:
Assuming the following question: Because of staffing decisions, managers of the Gibson-Marimont Hotel are interested in the variability in the number of rooms occupied per day during a particular season of the year. A sample of 20 days of operation shows a sample mean of 290 rooms occupied per day and a sample standard deviation of 30 rooms
Part a
For this case the best point of estimate for the population variance would be:

Part b
The confidence interval for the population variance is given by the following formula:
The degrees of freedom are given by:
Since the Confidence is 0.90 or 90%, the significance
and
, the critical values for this case are:
And replacing into the formula for the interval we got:
Part c
Now we just take square root on both sides of the interval and we got:

<u>Step-by-step explanation:</u>
Here we have , If the first step in the solution of the equation 2x - 8 = 5x + 3 is "subtract 2x," then in the form of a paragraph, explain in complete sentences the next steps necessary to completely solve the equation for x. Let's solve this :
2x - 8 = 5x + 3
⇒ 
⇒
{ subtract 2x from both side }
⇒ 
⇒ 
⇒
{ subtract 3 from both sides }
⇒ 
⇒
⇒
{ divide 3 from both sides }
⇒ 
Colors are Qualitative and Nominal: Qualitative, because there is no number involved for "color" and Nominal, because their is no natural ordering for color
Y - 8 =(-8/9)(x - 3)
y - 24/3 = (-8/9)x + 8/3
y = (-8/9)x + 32/3