Corn Growth Rate

1
Corn Growth Rate

• Simple Data Analysis
• by Yulia Tsutsa
• McMaster University
• March 2nd, 2006

2
Content

• Experiment and hypothesis
• Data Summary
• Paired t-test and confidence interval
• Conclusion

3
Experiment and Hypothesis

• Objective
• - find relation between growth hormone and corn
  cob size
• Experiment
• - 20 pots, 1 plant in each
• - 10 pots with hormone added, 10 without
• - Paired across the glasshouse
• Hypothesis
• - No difference in weight between treated and
  untreated plants.

4
Normal Q-Q Plotfor pair differences
Data Summary
Corn cobs weight (g)
5
Paired t-test CI

• Two-sided paired t-test
• p-value Pr( t9 t ) 0.052 gt 0.05
• 95 CI for pair difference
• (mean(diff) t0.975,9 SD/vn )
• (-38.210, 0.210),
• which contains zero

6
Conclusion

• At 5 level, no strong evidence that hormone
  treatment increases yield of corn cobs
• Observed difference could be reasonably explained
  as chance variation
• Suggestion need more samples to reduce chance
  variation and give a more accurate estimation