Some shrubs can resprout from their roots after their tops are destroyed. Fire is a serious threat to shrubs in dry climates, as it can injure the roots as well as destroy the tops. One study of resprouting took place in a dry area of Mexico.The investigators randomly assigned 12 shrubs to the treatment group and 12 shrubs to the control group. They clipped the tops of all the shrubs. They then applied a propane torch to the stumps of shrubs in the treatment group to simulate a fire. All the shrubs in the treatment group eventually resprouted but only 8 in the control group did.

• Display the data in a contingency table
• Can we use the large sample confidence interval to estimate the difference between the treatments? - Explain
• Calculate a 95% CI using the plus 4 method - be sure to include updated numbers (successes and trials)
• Calculate a 95% CI using the large sample method (original data) - what happens?
• Discuss how the two intervals are different and why one should be cautious when using technology.