Week Seven – Preparation, Expectations, and Activities

Recommended resources

• Review the material covered in the first talk
• Review the experiment on flagellar regeneration
• Fundamentals of graphing (pdf)
• Error representation and curvefitting (pdf)
• Background on the t test (independent samples; paired test)

Expectations – before the talk

• Be able to describe the experiment to be conducted this week, including experimental controls
• Be able to describe how a t test is used to test a hypothesis
• Be able to distinguish between a paired and unpaired t test

Expectations – following the talk

• Be able to describe the exact hypothesis to be tested this week
• Be able to describe the significance of each experimental control group
• Be prepared to decide which of the flagella regeneration data might best be analyzed using a t test
• Decide which type of t test (paired or unpaired) would be appropriate to use
• Decide what flagella regeneration data should be presented in graphical form
• Be prepared to represent the appropriate data and errors on a graph
• Be able to explain the rationale behind the hypothesis to be tested and to describe the design of the experiment to be conducted, including experimental controls

Sample problems

You are encouraged to test your understanding of hypothesis testing and use of "Student's" t test by reading the sample problems and addressing the questions. A link to a page with the solutions will be sent to the class after the talk. If you continue to have difficulty with the concepts after reading the solutions, then please seek assistance.

Recommended resources

• Consult the writeup on the flagella regeneration experiment when preparing your outline
• See specific recommendations for the writing assignments

Expectations

Previously, we have introduced quantitative methods in terms of "laboratory math" and quantitative representation of data. In fact, the more widely accepted definition of quantitative methods is related to statistical analysis of data.

You should be familiar with the biological model, the experimental design, use of the microscope for finding and measuring specimens. Resolve any questions you might have regarding experimental error and methods for data analysis. We have touched upon experimental design and data analysis in prior studies. Now we will conduct a focused, well controlled experiment to test a specific hypothesis.

Your prelab outline need only include the procedures that you used for fixing Chlamydomonas, preparing a wet mount of stained cells, finding cells, and measuring flagella. You may simply mark appropriate parts of your lab notebook if you already recorded sufficient detail.

Expectations

As you conduct the study each of you will be responsible for recording the deflagellation procedure, sampling/fixation procedure, and all other procedures employed in the laboratory. Record your own procedures for scoring samples and/or for preparing samples. You are responsible for recording and reporting all of the data that you and your team collect. In case of a problem, record names and contact information for other members of your research team.

Prepare to work with others on a team that is dedicated to one goal, that is to collect valid experimental and control data necessary to address our hypothesis. Prepare to communicate with other members of your team to ensure that data collection is complete and consistent. Plan to exercise appropriate safety practices including safe disposal of sharp glass.

Prepare to record and report raw data (length measurements) and any derived quantities with physically meaningful units and with appropriate precision. Have an idea of what the control data should look like, so that you can determine whether or not they make sense.

You are expected, of course, to take notes as you go along, so that all you need to do after collecting the last of the data is to finish entering the last set of data into your notebook, to write your summary, and to turn in your notebook pages (5 minutes or so).