An automobile mileage study tested the following hypotheses. Hypothesis Conclusion H 0: 25 mpg Manufacturer's claim supported H a: < 25 mpg Manufacturer's claim rejected; average mileage per gallon less than stated
For σ= 3 and a .02 level of significance, what sample size would be recommended if the researcher wants an 80% chance of detecting that μ is less than 25 miles per gallon when it is actually 24?

1. To find the rate of the cost per unit's decrease we need to find the slope of the graph for production levels above 12,000. We find the slope by dividing the change in y over the change in x. The two points that we will utilize for calculating the slope are the given points (12000, 0.85) and (38000, 0.59).



ANSWER: The rate of decrease is 0.00001 dollars per unit.

2. The function for the domain [12000, 38000] is just a linear equation that follows the form y = mx + b where m is the slope and b is the y-intercept. Since we have already calculated for the slope in the previous item, we will just compute the y-intercept. We will do this by using the point (38000,0.59) as our test point.






ANSWER: The function will then be

3. To know what the cost per unit when the company has produced 19,000 units already, we just use the function that we have built in the previous item. For this scenario, the value of x would be 19,000 and we are tasked to solve for y.



ANSWER: The cost per unit at the production level of 19,000 is 0.78 dollars.

4. This special growth incentive can be seen on the graph thru the decreasing cost per unit after the production level of 12,000. We can only assume that last year's average were 12,000 units therefore exceeding that production level decreases the cost per unit since the company's tax burden is decreased.

5. For questions 5 and 6 I have found the graph/function for the Seattle and Wichita Factory. They are attached here, respectively.

Knowing the cost per unit for every factory, we just compare the cost and pick the lowest one.

Wichita: $1 
Seattle: $0.75
Omaha:

ANSWER: We will send the order to the Seattle factory since they have the lowest cost per unit.

6a. For this subitem we are tasked to compare the cost per unit if we were to send two orders to a combination of any two factories. We will just find the cost per unit for every combination and show the average weighted cost by following the given formula.

Combination 1
Wichita: 7,000 units = $1
Seattle: 30,000 units = $0.68
Average Cost: $0.74

Combination 2
Wichita: 7,000 units = $1
Omaha: 30,000 units = $0.67
Average Cost: $0.73

Combination 3
Seattle: 7,000 units = $0.35
Omaha: 30,000 units = $0.67
Average Cost: $0.61

Combination 4
Omaha: 7,000 units = $0.85
Seattle: 30,000 units = $0.68
Average Cost: $0.71

Combination 5
Omaha: 7,000 units = $0.85
Wichita: 30,000 units = $0.80
Average Cost: $0.81

Combination 6
Seattle: 7,000 units = $0.35
Wichita: 30,000 units = $0.80
Average Cost: $0.71

6b. For this subitem we need to give all 37,000 units to one factory. We just need to calculate the cost per unit for every function. The calculation for the three factories is shown below (except when no calculation is needed, only inspection of the graph or function):

Wichita: not defined
Seattle: 
Omaha:

6c. For this item, we will review our answers for the two previous subitems and select the one with the lowest cost per unit. Upon examining, we can see that letting Omaha produce all 37,000 units will yield the lowest cost.

ANSWER: Orders B and C should be produced by Omaha's factory.
Total # of units produced for the company today: 37,000
Average cost per unit for all production today: $0.60