1
Data Analysis
Data Analysis
E3: Lab Lecture
• Suppose your hear that a high-protein diet during puberty leads to
an increased height as an adult.
- The mean height in a high protein tr eatment was 5’11” and the mean
height in a control treatment was 5’5”
- What would you feed your kids? How do you gauge this?
• The New York Times has just done an expose about sexism in
graduate admissions in a famous department of mathematics
- While the number of male and f emale applicants was equal, the
number of males admitted was greater.
- Should an formal inquiry take plac e? How do you evaluate the data?
How do we evaluate data?
• When you were a child, your father tells you he will let you stay up
late if the result of a coin he flips is heads.
- Suppose the coin comes up head s 25% of the time
- Is your Dad using a fair coin? H ow would you evaluate this?
12 3
100 25
4 1
Number of flips Number of “heads”
Control High-protein Control High-protein
♀
a
♂
a
Control High-
protein
♀
e
♂
e
frequency
Data Analysis
Data Analysis
Lecture Outline
•Processing Data (using Excel)
•Visualizing Data (using Excel)
•Analyzing Data (using Excel)
-Difference in means (t-test)
-Difference in distributions (χ
χχ
χ
2
test)
Data Analysis
Data Analysis
Lecture Outline
•Processing Data (using Excel)
•Visualizing Data (using Excel)
•Analyzing Data (using Excel)
-Difference in means (t-test)
-Difference in distributions (χ
χχ
χ
2
test)
Handling Data
• After a laboratory experiment or ti me out in the field, you
will have several data points.
• How should one process this (potenti ally voluminous) data?
- A first step to dealing with your data is to organize it
(spreadsheet programs, like Excel, can help)
- A second step is to process your data
1) Investigate portions of the data set
2) Look at relevant descriptive statistics
3) Transform data points in a well-defined way
4) Combine data points in a well-defined way
- A third step is to visualize your data
- A fourth step is to subject your data to an appropriate
statistical test
Massaging?
Dressing-up?
3F colonies
4N colonies
Fitness Across Two Environments
0
0.5
1
1.5
Tube Dish
Competition Arena
w(F,N)
*
Focusing
Worksheet
• Go to our class website:
http://faculty.washington.edu/kerrb/biol481/
• On the “Class Data” link, download the file labeled “Excel Practice Sheet”
•DEMO: Functions in Excel
•GOALS
- Get comfortable using f
x
line in Excel
- Understand the
“translational” properties
of Excel
- Learn to fix rows and
columns (or both) with $
•Fill in the empty boxes under the “Simple Functions” tab on the “Excel
Practic Sheet” file (you can check your work with your calculator).
