A store manager wants to know the percentage of shoppers who use coupons. He surveys everyone who enters the meat aisle. He finds that 60 percent of shoppers use coupons. Does the sampling method the store manager used support a valid inference?(1 point)

Question

Responses

No, because the sample is not chosen randomly.
No, because the sample is not chosen randomly.

No, because not all people who enter the meat aisle use coupons.
No, because not all people who enter the meat aisle use coupons.

Yes, because the sample contains coupon users and non-users.
Yes, because the sample contains coupon users and non-users.

Yes, because the manager asked everyone who entered the meat aisle.

A quality control manager wants to determine the percentage of defective light bulbs in the production line. Which of the following sampling methods would most likely lead to a valid inference?(1 point)
Responses

retesting 100 light bulbs that have already been tested
retesting 100 light bulbs that have already been tested

testing the last 4,000 bulbs in the production line
testing the last 4,000 bulbs in the production line

testing every fiftieth light bulb in the production line
testing every fiftieth light bulb in the production line

testing the first 2,000 light bulbs in the production line

Avery randomly selects 50 colored pencils from a basket and finds that 2 are not sharpened. If the basket contains 300 colored pencils, how many would you expect to be unsharpened?(1 point)
Responses

20
20

2
2

120
120

12

Answer 1

Let's analyze each question one by one.

1. Store Manager's Coupon Survey: The question concerns the validity of the inference made from surveying shoppers in the meat aisle. The appropriate response is:

   • No, because the sample is not chosen randomly.
   • Reasoning: The sample consists only of shoppers in the meat aisle, which may not accurately represent the overall population of all shoppers in the store.

2. Quality Control Manager's Sampling Method: The second question is about finding the best method to determine the percentage of defective light bulbs. The best response is:

   • testing every fiftieth light bulb in the production line.
   • Reasoning: This method ensures that every bulb has an equal chance of being selected, which makes it a random sampling method. The other options are biased and may not represent the entire production line.

3. Avery's Pencils Expectation: Avery randomly selects 50 colored pencils, finding that 2 are unsharpened. To find out how many would be expected to be unsharpened in a total of 300 colored pencils:

   • Proportion of unsharpened pencils = 2 unsharpened pencils / 50 total pencils = 1/25
   • Expected number of unsharpened pencils in 300 = 300 * (1/25) = 12.
   • Therefore, the correct response is:
   • 12.

So, the answers are:

1. No, because the sample is not chosen randomly.
2. testing every fiftieth light bulb in the production line.
3. 12.