Practicals 11: Linear models
Data are available in separate Excel fles
1. Number of seedlings per square meter was monitored at 24 grasslands, which were mown once
(mown1), mown twice (mown2) or grazed (varaible treatment). In addition, biomass production was
measured together with mean annual temperature of each grassland. Which of the grassland
parameters have signifcant efect on seedling 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. Efect 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. Efect of pehysical 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? Perform a statistical analysis including a variation
particioning to describe the predicor efects in detail.