For each of the following situations (all for comparing two means):

• State whether this is a paired or independent samples problem.
• What about the statement of the problem that led you to conclude this is a paired or independent samples problem. How do you know?
• Identify the parameter(s). Is it_dor is it₁and ₂?

1. Suppose you measure tread wear on two different types of bike tires. Twenty bikes get the first type of tire, and 20 bikes get the second set of tires. Then each bike is ridden by a different rider. After a period of 2 months, you measure the wear on the tires.
2. Suppose you measure tread wear on two different types of bike tires by putting both tires on the same bicycle. Then each bike is ridden by a different rider. After a period of 2 months, you measure the wear on the tires.
3. You randomly sample two different groups of people and test their computer skills. You take one random sample from people who have not taken a computer training course and record their test scores. You take a second random sample from another group of people who have completed the computer training course and record their test scores.
4. You randomly sample a group of people and test their computer skills. You record their test scores and then have them take computer training course. After the course, record their test scores again and compare the two scores.
5. People chosen in a random sample were asked how many minutes they had spent watching TV the day-before, and how many minutes they spent exercising. Researchers want to know how different the mean times are for these activities.
6. Researchers were curious about the best way for students to take notes, by hand (pen and paper) or with a computer. Student volunteers were randomly assigned to take notes either by hand or with a laptop while they watched videos of lectures. Then they took a test to measure their conceptual understanding.