Teacher resources and professional development across the curriculum

Teacher professional development and classroom resources across the curriculum

 A B C

Notes for Session 6, Part C

 Note 4 The activity in Part C provides an opportunity to consider the full statistical problem-solving process, with the primary focus on collecting the data. Useful data depend on an appropriate measurement/collection design, and you will have the opportunity to devise your own method of measurement. The activity asks you to consider several design options, and, in doing so, you will investigate such important ideas as randomization, blocking (pairing), and the effects of order. After completing the memory experiment in Part C, consider conducting your own memory experiment to determine whether your results confirm the results in our example. One option is to use the Interactive Activity in Session 1, Part C, and reexamine the distance perception phenomenon. A paired design similar to the one used for the memory experiment could be used to compare subjects' length perception of line segments with arrows to their length perception of line segments without arrows. Fathom Software, used by the onscreen participants, is helpful in creating graphical representations of data. You can use Fathom Software to complete Problems C7-C8, as well as Problem H1. For more information, go to the Key Curriculum Press Web site at http://www.keypress.com/fathom/.

 Note 5 Measurement is the most important part of the statistics problem-solving process. Poor measurement will certainly produce poor conclusions! Most introductory statistics books or courses do not put a major emphasis on measurement. In this course, we encourage you to take some time to focus on measurement; this activity is good place to do so.

Note 6

Groups or individuals working alone should discuss or reflect on the important ideas and issues of experimental design:

 • Using volunteers for subjects or personally selecting subjects might bias results. • The order in which tasks are performed may affect the outcomes of the tasks. • Pairing in data collection can reduce variation in measurements. In this case, each person is paired with him- or herself. This enables us to eliminate the differences in memory recall caused by the individual differences among subjects from any observed difference. • Random selection or assignment is intended to remove bias. Also, randomly assigning subjects to two groups is intended to average out their differences so that the two groups are more likely to be similar.

 Note 7 This is an informal analysis of results. Formal probability-based inferences were not considered. However, the issues of generalizing any results to a larger population need to be raised. What is the population? How general are the results? A more advanced analysis is required to make an inference about any larger population that our results might represent.