Egyptians Some archaeologists theorize that ancient Egyptians interbred with several different immigrant populations over thousands of years. To see if there is any indication of changes in body structure that might have resulted, they measured 30 skulls of male Egyptians dated from 4000 b.c.e and 30 others dated from 200 b.c.e. (A. Thomson and R. Randall-Maciver, Ancient Races of the Thebaid, Oxford: Oxford University Press, 1905) a) Are these data appropriate for inference? Explain. b) Create a 95% confidence interval for the difference in mean skull breadth between these two eras. c) Do these data provide evidence that the mean breadth of males skulls changed over this period? Explain.

STAT 110 – Notes for Week of 9/6/16 Chapter 6 Continued o You can only generalize results (apply statistics from a sample to an entire population) if the results are: Statistically significant Useful The sample that produced the results is representative of the population The experiment that produced the results was similar enough to real life o Completely Randomized Experimental Design: a type of experimental design where all of the subjects are randomly allocated among the treatments. This type of design allows more than one treatment (treatment combinations) to be isolated and studied at the same time.