flies
food	eyeSpan
corn	2.15
corn	2.14
corn	2.13
corn	2.13
corn	2.12
corn	2.11
corn	2.1
corn	2.08
corn	2.08
corn	2.08
corn	2.04
corn	2.05
corn	2.03
corn	2.02
corn	2.01
corn	2
corn	1.99
corn	1.96
corn	1.95
corn	1.93
corn	1.89
cotton	2.12
cotton	2.07
cotton	2.01
cotton	1.93
cotton	1.77
cotton	1.68
cotton	1.64
cotton	1.61
cotton	1.59
cotton	1.58
cotton	1.56
cotton	1.55
cotton	1.54
cotton	1.49
cotton	1.45
cotton	1.43
cotton	1.39
cotton	1.34
cotton	1.33
cotton	1.29
cotton	1.26
cotton	1.24
cotton	1.11
cotton	1.05

Stalk-eyed flies (*Cyrtodiopsis dalmanni*) have eyes at the ends of long stalks that extend horizontally from each side of the head. Longer eye spans (the combined lengths of stalks from tip to tip) enhance attractiveness to mates and success in competitive interactions. Is eye span affected by the quality of food that flies eat? To find out, researchers reared two groups of flies on different foods, then recorded each fly's eye span in millimetres. One group of flies was fed corn (a high-quality food), while the other group of flies was fed cotton wool (a low-quality food).

**EXERCISE 1: Based on the research description above, what are the null and alternate hypotheses of interest? (2 MARKS)** [Enter your response here] **EXERCISE 2: Report (with standard errors) the estimates that are the focus of the hypotheses above. You can work out your answer using the chunk below. (2 MARKS)** [Enter your response here] # Use this chunk to complete Exercise 2 **EXERCISE 3: What is the appropriate statistical analysis for testing the null hypothesis? Give 3 reasons to justify your answer. Assume that the numerical variable has a normal distribution. You can work out your answer using the chunk below. (4 MARKS)** [Enter your response here] # Use this chunk to complete Exercises 3, 4, and 5 **EXERCISE 4: After running the appropriate statistical analysis (which you can do in the chunk above), do you reject or fail to reject the null hypothesis? Why? Explain what this indicates about the relationship between food and eye span in stalk-eyed flies. (2 MARKS)* * [Enter your response here] **EXERCISE 5: Based on the research description and your analysis of the data, write a brief report of the results as though it was your own study. Follow the guidelines in the week 7 workshop handout for reporting the results of a statistical analysis, providing all information necessary for readers to understand and properly evaluate the research outcomes. Be sure to use your own words (do not copy the week 7 workshop handout). There is no minimum or maximum word limit, but a few sentences should suffice. (4 MARKS)** [Enter your response here]