Question

Answer these questions:

1. Do you see evidence of an association between the amount of fish in a man's diet and his risk of developing prostate cancer?

2. Does this study prove that eating fish does NOT prevent prostate cancer? Explain clearly.

USE R

CODE FOR DATA IS HERE:

fish = read.csv("http://www.datadescant.com/stat104/Fish_diet.csv")
fish = fish[-1, ] #remove first row
fish$Col1 = droplevels(fish$Col1) #remove unused factor levels
fish$Col2 = droplevels(fish$Col2) #remove unused factor levels

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REST OF THE QUESTION HERE (part a), b), d):

T 40. Fish di Fish diet Medical researchers followed 6272 Swedish men for 30 years to see if there was any association between the amount of fish in their diet and prostate cancer. ("Fatty Fish Consump- tion and Risk of Prostate cancer." Lancet. June 2001) SC 14 Fish Consumption Never/Seldom Small Part of Diet Moderate Part Large Part No Prostate Prostate Cancer Cancers 110 2420 201 2769 50742 209 a) Is this a survey, a retrospective study, a prospective study, or an experiment? Explain. b) Is this a test of homogeneity or independence?

Answer 1

1)

fish = read.csv("http://www.datadescant.com/stat104/Fish_diet.csv")
fish = fish[-1, ] #remove first row
fish$Col1 = droplevels(fish$Col1) #remove unused factor levels
fish$Col2 = droplevels(fish$Col2) #remove unused factor levels
table(fish$Col1,fish$Col2)
chisq.test(table(fish$Col1,fish$Col2))

Pearson's Chi-squared test

data:  table(fish$Col1, fish$Col2)
X-squared = 3.6773, df = 3, p-value = 0.2985

since p-value = 0.2985 > alpha

hence we fail to reject the null hypothesis

we conclude that there is not sufficient evidence of an association between the amount of fish in a man's diet and his risk of developing prostate cancer