1. A factory manufactures a chip used in constructing central processing units for computers. The factory's quality control division has set a limit that no more than 2% of the chips can be defective. They sample 200 computer chips and find that 3 of them are defective. They use this data to calculate the following 90% confidence interval: (0.001, 0.029). Recommend a strategic decision for the factory.
a. The factory should continue producing the chips using the same process since the confidence interval shows that the proportion of defective chips could be very close to 0%.
b. The factory should continue producing the chips using the same process since 3 defective chips out of 200 is 1.5%, which meets the goal of no more than 2% being defective.
c. The factory should consider revising its production process since there is a 90% chance that 2.9% of their chips are defective.
d. The factory should consider revising its production process since the confidence interval shows that the proportion of defective chips could exceed 2%.
2. Sylvia makes pizzas at an Italian restaurant. A large pizza is listed on the menu as being 16 inches. Sylvia wants to know how accurate she is at throwing dough to that size. A coworker measures all the pizzas Sylvia throws, and they randomly select 35 data points. They use this data to calculate the following 95% confidence interval: (15.85, 16.10). Use this to recommend a strategic decision.
a. Sylvia should use more dough since the least value of the confidence interval is less than 16 inches.
b. Sylvia should use less dough since the greatest value of the confidence interval is greater than 16 inches.
c. Sylvia should continue using the same amount of dough since 16 inches is contained within the confidence interval.
d. Sylvia should use more dough so that the entire confidence interval is greater than 16 inches.
3. A bus company is doing research to determine if it can save money by switching from gasoline-powered buses to electric-powered buses. The company randomly selects records of gasoline usage from 30 days and calculates that the buses use a mean 22 gallons of gas each day with a standard deviation of 1.8 gallons. The gas station the buses use charges $2.95 for a gallon of gas. The company also knows it would cost $62 to charge the buses enough to be able to run for one day.
Use a 95% confidence interval to recommend a strategic decision for the bus company.
a. The bus company should switch to the electric buses because 22 gallons of gas costs more than $62.
b.The bus company should switch to the electric buses because the least amount of mean gas per day in the confidence interval costs more than $62.
c. The bus company should not switch to the electric buses because the least amount of mean gas per day in the confidence interval costs less than $62.
d. The bus company should not switch to the electric buses because the greatest amount of mean gas per day in the confidence interval costs less than $62.
D
C
B