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:
Answer:
Combine like terms.
Step-by-step explanation:
3x+2y=16
You'd simply have to find 20% of $40. To find the percent of a number, you would change the percent into an actual decimal/number, and then multiply them both. So the percent would become 0.20.
40 × 0.20 = 8
So now you would subtract 8 from the cost of 40.
40 - 8 = 32.
The shirt costs $32.
Answer:
300
Step-by-step explanation:
each ten is worth 10 so 10x30+ 300
plz mark brainliest