Week 10: Insect genetic diversity across the globe

Group project schedule

Lab outline

• Descriptive statistics

• Descriptive statistics in Excel

• Worksheet overview

• To-do for next week

Make sure to fill out the weekly survey, so I can take attendance.

Descriptive statistics

Describe and analyze a dataset’s main features and characteristics without making any generalizations or inferences to a larger population

• Central tendency

• Variability

As opposed to inferential statistics, which tries to make generalizations and describe a larger population.

Central tendency- the center of a distribution of data. Mean, median.

Variability- the spread of a distribution of data. Variance, standard deviation, range

There are others, like counts, but these are the main descriptive statistics you will encounter.

We’ve calculated some of these already- the average, sum, counts.

Central tendency

Mean (aka average)- the sum of the values divided by the number of values

Median- the middle value in the data set

• if there are an even number of values, add the two middle values and divide by two
• the mean is more influenced by outliers than the median

Variability

Standard deviation- how much variation a random variable is expected to have around its mean

There is an equation that describes the standard deviation, but that is beyond the scope of this lab.

Also range- maximum value minus the minimum value

Descriptive statistics in Excel

You can get these in PivotTables or with Excel functions. I’ll demonstrate PivotTables to you.

Worksheet overview

To-do

• Upload Lab Worksheet and Excel spreadsheet to Blackboard by next lab (04/03)

• Continue data collection

• Weekly lab survey is your ticket out (and attendance!)

• Speaker questions before the end of class on Monday