GENERAL ECOLOGY LABORATORY
STATISTICS PROBLEM SET
FALL SEMESTER
Page numbers listed below relate to the lab manual. Use these to find the necessary procedure and an example.
1. You have a great wealth of plant height and flower length data, gathered from Common Mullein on the Prairie Island flood control dike. Keep your plant height and flower length measurements in two, separate groups (based on year) for analyses.
A) For each year (2022 and 2023), calculate the mean plant height and the mean flower length (p. 7).
B) For each year (2022 and 2023), calculate the standard deviations for
plant height and flower length (p. 8).
C) Determine whether or not mean plant height or mean flower length
differs between the two years of plants by using a t-test to compare plant
heights and another t test to compare flower lengths (p. 11).
2. Next use all of your plant height data from both years, but keep values separate by year. Determine the range of plant heights (tallest minus shortest) separately for each year and divide each of those ranges into 5 equal increments. Count the total numbers of plants in each of the five height categories (short, medium-short, medium, medium-tall, tall). Again, do this separately for each year.
A) Analyze these data with the aid of two Chi-square tests to determine if equal numbers of plants are in each height category for each of the two years of plants (p. 14).
3. For both years of plants, pair up all of your plant height and flower length data (one pair of measurements for each plant). This is most easily accomplished in a spreadsheet by having the plant heights for one year in one column and the corresponding flower lengths for that same year in an adjacent column.
A) Calculate a regression equation for the relationship between plant height (X) and flower length (Y) for each year separately (p. 17).
B) Using the equations for each species, predict how long the flower
lengths should be in plants with 90 cm and 195 cm heights (p. 18).