Quiz3

The data set is from a case-control study of smoking and Alzheimer’s disease. The data set has two variables of main interest:

• smoking a factor with four levels “None”, “<10”, “10-20”, and “>20” (cigarettes per day)
• disease a factor with three levels “Alzheimer”, “Other dementias”, and “Other diagnoses”.

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Q1 Describe the largest group that has other dementias. Discuss it by number of cigarettes per day.

The largest group of all dementias is non smoker alzhhiemers. The plot is larger than the smoking alzhiemers patients ## Q2 Describe one group that has more cases than expected given independence (by chance). Discuss it by number of cigarettes per day.

People with dimentia that smoke more than 20 cigarettes per day.

Q3 Does smoking seem to matter in determining other dementias? Discuss your reason using the masaic chart above.

If you smoke you seem to be less likely to have alzhimers, as the majority of alzhiemers patients do not smoke

Q4 Create correlation plot for RailTrail.

Hint: The RailTrail data set is from the mosaicData package.

Q5 List all four variables that have negative correlation with the number of trail users (volume).

High, average, low tenp and summer have high correlation

Q6 What season seems to be least popular for trail users?

spring is the least popular seeason for the trail

Q7 The correlation coefficient between hightemp and cloudcover is quite small. Would you be sure that

the two variables are not related at all? Hint: One word answer (e.g., yes or no) is NOT enough. Explain why. Yes, this is most likely because its not usually cloudy when its hot because clouds burn off.

Q7.a Continued from Q7. Create scatter plot. After examing the scatter plot, would you conclude that the two variables are not related at all?

Hint: Discuss your reason by explaining your scatter plot. After looking at the scatter plot, you can see that cloud cover and high temp are not related because there is no possible line of best fit.

Q8 Hide the messages, the code and its results on the webpage.

Hint: Use message, echo and results in the chunk options. Refer to the RMarkdown Reference Guide.

Q9 Display the title and your name correctly at the top of the webpage.

Q10 Use the correct slug.