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”.

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

the largest group to have other dementias would be the group that is none smokers.

Q2 Describe one group that has more cases than expected given independence (by chance). Discuss it by number of cigarettes per day.

one group that has more casses than expected given independence would be people diagnosed with other dementias that smoke 20 cigarettes or more

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

there seem to be more cases of other dementias the more ciggaretts one smokes. however the largest group diagnosed are people that smoke no cigarettes. this would lead me to believe that there is not a very strong linear correlation amoung smoking and other dementias.

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).

Spring, fall, cloud cover, and precipitation all have a negative correlation with trail users/ volume.

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

it would seem that fall would be the least popular season. I would come to this conclution because it has a negative correlation of -.25. howevwe this is not a strong correlation.

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.

the correlation coefficient is -.1 this would be a very weak linear negative correlation. I would not be sure that there is no correlation at all though. there could in fact be a non lineare correlation that was stronger than -.1. One could test this theory through a scatter plot.

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.

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.