Question

CHOOSING THE DESIGN OF AN EXPERIMENT

A teacher believes that whatever he says in class has no effect on his students. Just as he's about to quit his profession, a statistician enters the room and suggests that the teacher design a study to test his assumption. The study will look at whether providing in-class feedback on homework assignments enhances classroom performance.
The teacher wants to know whether providing feedback before or after returning the assignments is most useful.
He's also interested in the most effective means of presenting the feedback: verbal presentation, written handout, or a summary on overheads.
Ultimately, he'd like to identify the best approach for increasing test scores of the students. The teacher has six classes on his schedule.
Design an experiment that helps answer these questions. Be sure to identify the factors, the levels of the factors, the treatment groups, and the response variable.
Considering the teacher doesn’t want to get fired, does a control group seem plausible (or ethical) in this scenario?
Considering students’ schedules cannot be adjusted and classrooms consist of many students, comment on how the students will be assigned to the different treatment groups. Why would it not be possible to use simple random assignment of all students?
As much as possible, use diagrams instead of words to summarize your experimental design.

Answer 1

every thing is in explanation

Step-by-step explanation:

**Experimental Design:**

1. **Factors and Levels:**

- **Factor 1: Timing of Feedback**

- Level 1: Before returning assignments

- Level 2: After returning assignments

- **Factor 2: Means of Presentation**

- Level 1: Verbal presentation

- Level 2: Written handout

- Level 3: Summary on overheads

2. **Treatment Groups:**

- Group 1: Before + Verbal

- Group 2: Before + Written

- Group 3: Before + Summary

- Group 4: After + Verbal

- Group 5: After + Written

- Group 6: After + Summary

3. **Response Variable:**

- Classroom performance measured by test scores.

4. **Control Group:**

- Given the ethical concerns and the teacher's preference, a pure control group without any form of feedback might not be suitable. However, a 'traditional feedback' group where feedback is provided in the usual manner (neither before nor after, with the usual means) can serve as a reference point.

**Assignment of Students:**

- Due to practical constraints, simple random assignment may not be feasible.

- Use a matched pairs design where each class is treated as a pair (e.g., Morning class and Afternoon class).

- Randomly assign one class from each pair to each treatment group.

- This helps control for potential class-specific factors that might affect the results.

**Diagram:**

```

Timing of Feedback

-----------------------------------------------

| | | |

Means of Presentation | | |

| | | |

-----------------------------------------------

| | | | | | | | | | | | |

B1V B1W B1S B2V B2W B2S A1V A1W A1S A2V A2W A2S

B = Before, A = After, V = Verbal, W = Written, S = Summary

```

This design helps explore the combined effects of timing and means of presentation on classroom performance while accounting for class-specific variations.