Statistical Investigation Data Collection Activity Day 1

Step 1: Formulate Question Let’s Review: What makes a question a statistical question?

Step 1: Formulate Question Question should focus on data that will vary, or change, from one measurement or response to the next. Statistical Question: “How much glass do the households in our town tend to recycle?“ What will be measured: The weight of glass per household in next week’s pick up of recyclables. How measured: Residents will record weight of glass in their recycle bin next week and submit their measurement. Some reasons data will vary: some families may use more glass containers than other types of containers, households will vary in how many people live there, and families will differ in the accuracy of their measurement.

Step 1: Formulate Question Should require a statistical study—you cannot look up an exact answer in a book or on a website or get an exact answer from an individual. Statistical Question: “How much glass do the households in our town tend to recycle?“ Non-statistical Question: “What types of materials did our town recycle last week?”

Step 2: Collect Data Identify variable Decide on the data that will best capture the variable Consider different study designs: descriptive study or experiment Choose to collect data from entire population or sample Determine data collection strategy: ask questions or observe Take care in collecting data Record data

Step 2: Collect Data Statistical question: “How long can middle grade students hold their breath under water?” What is the variable? What data should we use? (and is it numerical or categorical?)

Step 2: Collect Data Statistical question: “How long can middle grade students hold their breath under water?” What is the variable? Length of breath-holding What data should we use? (numerical or categorical?) Numerical – number of seconds breath held

Step 2: Collect Data Consider different study designs Designs: descriptive study or experiment

Step 2: Collect Data Consider different study designs Designs: descriptive study or experiment “How does swimming a 50 meter race before holding their breath under water affect how long middle grade students can hold their breath under water?” “How long can middle grade students hold their breath under water?”

Step 2: Collect Data Choose who to collect data from entire population sample Determine data collection strategy ask questions observe Take care in collecting data instruments/tools precision range of data consistency

Statistical Investigation Data Collection Activity Day 2

Summary What changes would you make to how you collected data another time? Were our procedures for collecting data clear enough – did we all collect and record data in the same way? Did the data we collected help us answer our question? Do we need additional data? Would it have helped to be more precise (e.g., recording the number of seconds)? Why or why not? Would it have helped to be less precise (e.g., rounding to the nearest hour)? Why or why not?

Summary What are examples of how you would collect data differently if the question about sleep was different? What would we do for the following questions: How does the amount middle grade girls sleep compare to the amount middle grade boys sleep? How does the amount parents and middle school students sleep compare? How does the amount of sleep the night before and after a big test compare? How many hours before midnight do middle school students sleep per night?