AP Biology Lab #1: Observations on Plant Growth and Development
Purpose
The purpose of this assignment is to introduce you to the skills you will need to successfully complete
and get the most from your laboratories including:
 Data collection
 Data analysis using statistics
 Experimental design
 Presenting your work through lab reports
Objectives
 Apply mathematical routines to quantities that describe natural phenomena
o Mean, median, standard deviation, Chi-square
o Graphing, line of best fit, error bars
 Pose, refine, and evaluate scientific questions
 collect data to answer a particular scientific question
 analyze data to identify patterns or relationships
 justify claims with evidence
 construct explanations of phenomena based on evidence produced through scientific practices
Your answers to the questions in the section below will be completed in your lab notebook, which is a record of all of
your thinking, data, and analysis. You will use these notes when you are completing your lab report. It is extremely
important for you to document your thinking because you may forget something if you don’t write it down.
I. Before you look at your data
You have been watching and observing your plant throughout its life. What you have completed
is an observational study. Data collected during an observational study are called field notes,
and are usually used to generate questions. This type of study can be completed with or without
a hypothesis to test.
You may have noted many of your thoughts during this process in your notebook, or perhaps
your noted them only in your mind (for the future: write everything down, you never know when
inspiration may strike!). Think about some of the thoughts you had while your plant was
growing and describe them in your lab notebook. These questions will likely be the hypotheses
you are testing with the data you collected.
II. Examining your data without statistics
Before you begin to do any calculations you should first look closely at the information you
collected. When we collect data with no particular question in mind we can’t really do much with
it unless we have something to ask. Here are some questions you should consider whenever you
look at data you have collected.
a. Are there any patterns and trends (a trend is a pattern in the data) at a glance?
b. How does your data compare to others with the same type of plant?
c. How does your data compare to others with different types of plants?
d. What do you wonder about after looking at your data? (Here is where we can come up
with a question that we can test with statistics.)
III. Statistical Analysis of Your Data
a. After looking at your data, think about some of the trends that you observed. How can
you use the data you collected, or perhaps comparison of your data with someone else’s to
prove that those trends really exist?
Adapted from Partnerships for Reform through Investigative Science and Math by Samantha Fedor
b. For each metric (characteristic you measured), find the mean, median, mode, and
standard deviation if appropriate. Show your work in your lab notebook.
c. Use Excel to graph your data. Think carefully about your metrics. What might be the
best type of graph for the data you collected?
d. What are some of the questions that you asked in the sections above? How can you use
your data and statistics to test those questions? Do the calculations for those questions
and make sure to keep all of your work along with your conclusions in your notebook.
e. What are some potential sources of error that may have affected the data you collected
during your study and how may they have affected it?
IV. Conclusions
a. What are some conclusions you can make about plant growth based on your data and
your statistical analyses?
b. What evidence supports these conclusions?
V. Next Steps
a. What questions about plant growth (either about your species, or plant growth in
general) do you have after completing your study?
b. If you were to complete this assignment again, how might you improve your study?
Adapted from Partnerships for Reform through Investigative Science and Math by Samantha Fedor