Practicals 11: Linear models
Data are available in separate Excel files
1. Number of seedlings per square meter was monitored at 24 grasslands, which were mown once
(mown1), mown twice (mown2) or grazed (variable treatment). In addition, biomass production was
measured together with mean annual temperature of each grassland. Build a multiple regression model
predicting the effects of grassland parameters on seelding density.
2. Transpiration of plants was recorded together with air humidity, temperature, wind speed and it
weather (sunny vs. cloudy). On which of these variables does the transpiration rate depend?
3. Effect of watering and fertilizer application on plant growth (measured by biomass production) was
tested in full-factorial manipulative experiment. Perform two-way analysis of variance and test also the
interaction between the two treatments.
4. Effect of physical excersise and diet was studied on body mass was studied in 21 people. In addition
to the studied variables, body height, hair colour and sex was also recorded as pressumed important
covariates. What does the body mass depend on?