Consider the data found in the file NYC Trees Data. Suppose you want to compare the tree diameter of the two types of trees. Is the average tree diameter of a Norway Maple larger than the tree diameter of a Honey Locust?

DATA BELOW

1. Identify the variables, categorical or quantitative?

• Explanatory:

• Response:

2. Is this an experimental study or observational study? Explain.

3. State the parametr in words ( ). Take note of the symbol!

4. Write the null and alternative hypothesis in symbols and words.

Copy the entire dataset into the Multiple Means Applet.

5. Compare the two histograms. Which tree appears to have a higher average diameter? Are there any outliers?

6. Identify the following from the applet:

= __________ = __________ = ___________ = __________ = __________ = ___________

7. Calculate the observed difference and assign a symbol. Note: this is our observed statistic!

8. Are the validity conditions for the theory based approach met? Explain, be specific!

Use the information in question 6 to fill out the Theory Based Inference Applet.

9. Based on the applet, what is our p-value. Do we reject or fail to reject?

10. Calculate the standard error.

11, Based on the applet, what is our standardized statistic (t-statistic)? Show by hand how to obtain this value. Do we reject or fail to reject?

12. Based on the applet, what is the 95% confidence interval? Show by hand how to obtain this. Do we reject or fail to reject?

13. Interpret the confidence interval.

14. Do the conclusions based off your p-value, standardized statistic, and confidence interval match? Explain.

15. Write a conclusion in context of the research question.

DATA-

Species Diameter Norway_maple 7 honeylocust 13 honeylocust 13 honeylocust 12 Norway_maple 11 honeylocust 7 honeylocust 5 honeylocust 10 Norway_maple 11 honeylocust 6 honeylocust 6 honeylocust 14 honeylocust 9 honeylocust 3 honeylocust 13 Norway_maple 11 Norway_maple 10 honeylocust 16 honeylocust 10 honeylocust 5 honeylocust 11 honeylocust 11 honeylocust 12 honeylocust 3 Norway_maple 8 honeylocust 7 Norway_maple 11 Norway_maple 16 honeylocust 14 honeylocust 8 honeylocust 10 honeylocust 14 honeylocust 15 honeylocust 4 Norway_maple 14 honeylocust 8 Norway_maple 6 honeylocust 17 honeylocust 7 Norway_maple 10 honeylocust 17 Norway_maple 10 honeylocust 4 Norway_maple 11 honeylocust 14 honeylocust 6 Norway_maple 8 Norway_maple 10 honeylocust 10 honeylocust 14 Norway_maple 14 honeylocust 2 honeylocust 12 Norway_maple 10 honeylocust 12 Norway_maple 21 Norway_maple 13 honeylocust 5 honeylocust 6 honeylocust 22 Norway_maple 16 honeylocust 11 Norway_maple 18 honeylocust 5 honeylocust 5 honeylocust 5 Norway_maple 24 honeylocust 10 Norway_maple 12 honeylocust 12 honeylocust 12 Norway_maple 9 honeylocust 9 Norway_maple 11 honeylocust 13 honeylocust 12 honeylocust 7 Norway_maple 22 honeylocust 15 honeylocust 12 honeylocust 7 Norway_maple 16 honeylocust 11 Norway_maple 9 Norway_maple 15 honeylocust 8