Practice with
Regression Analysis
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Answer the following questions dealing with Regression Analysis.
Grab your graphing calculator.

1. Which of the following graphs would have a negative linear correlation closest to negative one?
Choose:

 

 

 

2. The table shows the amount of medicine for treating a disease in the bloodstream over the 9 hours following a dose of 10 mg.  It seems that the rate of decrease of the drug is approximately proportional to the amount remaining.

a.) Use this information to find a suitable function to model this data.

b.) Using your model, when will there be less than 1 mg. of the medicine in the patient's bloodstream?

c.) If the initial does was 15 mg., when would the amount of the medicine in the bloodstream fall below 5 mg?

Express answers in this question rounded to three decimal places.  

Time
(hrs)
Drug Amount
(mg)
0 10
1 8.3
2 7.2
3 6.0
4 5.0
5 4.4
6 3.7
7 2.8
8 2.5

Answer

 

 

3. A factory is producing and stockpiling metal sheets to be shipped to an automobile manufacturing plant.  The factory ships only when there is a minimum of 2,050 sheets in stock at the beginning of that day.  The table shows the day, x, and the number of sheets in stock, f (x), at the beginning of that day.

a.)  Write a linear regression equation for this set of data, rounding coefficients to four decimal places.

b.)  Use this equation to determine the day the sheets will be shipped.

Day Sheets in Stock
1 860
2 930
3 1000
4 1150
5 1200
6 1360

Answer

 

 

4.

 Since January 1980, the population of the city of Brownville has grown according to the mathematical model ,
where x is the number of years since January 1980.

a.)  Explain what the numbers 720,500 and 1.022 represent in this model.

b.) If this trend continues, use this model to predict the year during which the population of Brownville will reach 1,548,800.


Answer

 

 

5.

According to the National Weather Service, the 2005 average monthly temperature in degrees Fahrenheit at Central Park in New York City is given below:
 

Month Jan. Feb. March April May June July Aug. Sept. Oct. Nov. Dec.
Average
Temp (º F)
31.3 36.5 39.4 55.1 58.9 74.0 77.5 79.7 73.3 57.9 49.6 35.3

a.)  Write a sinusoidal function that models the average monthly temperature, using t = 1 to represent January.  Round values to three decimal places.

b.)  According to your model, what is the average temperature in December?

c.)  Explain the discrepancy from  your model to the average monthly temperature in December?

Answer 

 

 

6. At the local arcade, the most popular video game is Cosmic Blaster.  Joshua decides to observe new game players using the machine every half hour and record their highest scores.

a.)  Find an equation to model the data.

b.)  According to your model, what score would most likely be observed at 8:15 pm?  Answer to the nearest integer.

c.)  Joshua makes the assumption that the more expert players use the machine later in the evening.  Does the data support this hypothesis?
 



Answer

Time Score
4 pm 950
4:30 pm 1001
5 pm 1450
5:30 pm 1503
6 pm 1605
6:30 pm 3002
7 pm 2668
7:30 pm 2860
8 pm 3250
8:30 pm 3945
9 pm 4720
9:30 pm 4866
10 pm 5509