Study questions

1. Using CS6Data2 categorise cows into high-high; low-high; high-low and low-low concentrate-fed groups. The high-high etc. periods should correspond to weeks 1-14 and weeks 15 onwards, respectively. Having calculated mean values for each cow over these two periods you will need to decide on suitable high/low ranges for each period so that there are reasonable numbers of cows in each group. Justify your groupings.

2. Using the results of question 1, calculate average Wood lactation curves for each group. Comment on any differences in regression coefficients. How might you determine whether the coefficients are statistically significant?

3. Prepare a letter that you might send to the authors of the Romney et al. publication explaining your observations from the analyses carried out in this case study.

4. Prepare a report suitable for presenting to the farmers outlining some of the results obtained in this case study.

5. Describe the checks that you would include in a database system that you might have written to handle the data collected during the monitoring period. Describe any interim summary reports that you think would be useful to have during the course of the study that might have been informative to the researchers.