Evaluation 1

1. Explain what is a statistical pattern. Your explanation should note how a statistical pattern differs from what is typically meant by "pattern".
2. What does it mean, in statistics, that an event is "unusual"? (We know that unlikely, unexpected, and rare are synonyms of unusual, so mentioning them will not answer the question. Please explain the meaning, don’t just give synonyms.)
3. Here is a scenario:

   A consumer agency purchased 20 pairs of RoadRunner in-line skates from sports retailers chosen at random across the U.S. It found that 10% of the pairs (i.e., two) had defective wheels. However, the skate manufacturer claims that its tests show that no more than 2% of all RoadRunner pairs it distributes have defective wheels.

   1. Was there a sample chosen in this scenario? If so, identify it.
   2. If a sample was chosen, what was the population from which it was drawn?
   3. In this sceneario:
      
      "10%" refers to 10% of what?
      
      "2%" refers to 2% of what?
   4. What is at issue between the consumer agency and the manufacturer?
   5. Here is a question. Don’t answer it!

      How unusual would a result like the consumer agency’s be if, as the skate manufacturer claims, only 2% of all RoadRunner pairs have defective wheels?

      Describe, in principle, how you would use ProbSim to investigate the question. (You don’t need to provide details of setting up ProbSim. You’ll provide that information in the next question. Instead, focus on the overall logic of your strategy.

   6. Fill in the blank ProbSim window below as you actually would to investigate this question:
   
4. The screen below shows results of having analyzed data generated by ProbSim to investigate the in-line skates issue. The data was generated under the assumption that the manufacturer’s claim is accurate. In this screen, "B" stands for "bad wheels".

   

   1. How many samples were drawn?
      
      How large was each sample?
   2. Interpret the line that is second from the bottom.
   3. Based on these results, answer this question:

   How unusual would a result like the consumer agency’s be if, as the skate manufacturer claims, only 2% of all RoadRunner pairs have defective wheels?