Henry wants to find the average time it takes West High School students to run a lap around the track. So he will consider 40 students to find the average time. Answer the questions below. \( \begin{array}{l}\text { (a) Which unit(s) could be used for the unit of measurement? Check all that apply. } \\ \square \text { pounds } \\ \text { (b) Which of the procedures below would be the best way to find the average time? } \\ \text { Measure the times of } 40 \text { volunteers who run a lap around the track. } \\ \text { Ask for } 40 \text { volunteers to run a lap around the track and have them state their own times. } \\ \text { Randomly pick } 40 \text { students to run a lap around the track and have them state their own times. } \\ \text { Randomly pick } 40 \text { students to run a lap around the track and measure their times. }\end{array} \)

Let's break down the problem step by step. ### Part (a): Units of Measurement To find the average time it takes for students to run a lap around the track, we need to consider appropriate units of time. The options provided include "pounds," which is a unit of weight and not relevant for measuring time. **Possible units of measurement for time include:** - Seconds - Minutes Thus, the correct answer for part (a) is: - **Seconds** - **Minutes** ### Part (b): Best Procedure to Find Average Time Now, let's evaluate the procedures listed for finding the average time: 1. **Measure the times of 40 volunteers who run a lap around the track.** - This method relies on volunteers, which may introduce bias if the volunteers are not representative of the entire student population. 2. **Ask for 40 volunteers to run a lap around the track and have them state their own times.** - This method is also biased because it relies on self-reported times, which may not be accurate. 3. **Randomly pick 40 students to run a lap around the track and have them state their own times.** - While this method uses random selection, it still relies on self-reported times, which can lead to inaccuracies. 4. **Randomly pick 40 students to run a lap around the track and measure their times.** - This is the best method because it combines random selection (to ensure a representative sample) with actual measurement of times (to ensure accuracy). **Conclusion for part (b):** The best procedure to find the average time is: - **Randomly pick 40 students to run a lap around the track and measure their times.** ### Summary of Answers - **(a)** Units of measurement: Seconds, Minutes - **(b)** Best procedure: Randomly pick 40 students to run a lap around the track and measure their times.