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:
Lets assume center point of circle as O
OD is the radius of circle . so OD is also 7
All the sides of the triangle are equal . so angle at the center O is 60 degree.
radius = 7
Length of arc CD = 
= 
= 
= 
Given:
Time spend on every 2 questions = 5 minutes.
To find:
The missing values for the given table.
Solution:
Let x be the number of questions and y be the number of minutes.
We have,
Time spend on every 2 questions = 5 minutes
Time spend on 1 question = 
minutes
Time spend on x questions = 
minutes
Now,
For x=0,
For x=1,
For x=2,
For x=3,
For x=4,
Therefore, the required table is
Questions : 0 1 2 3 4
Time (minutes) : 0 2.5 5 7.5 10
The formula for a cone is pi * r^2 * (h/3) or pi* r^2 * h * 1/3.
Since the height is 7ft and the radius if 4ft you plug those into the equation and get:
V= 1/3 * pi * (4^2) * (7)ft cubed which is the answer of B
