Quiz 3

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.

People that are not smoking cigarettes has the largest group. 0 cigarettes per day.

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

Other dimensias greater than 20 cigarettes per day.

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

Smoking does not matter in determining dementias. There are some relationships but they are small.

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).

Fall(-.25), Spring (-.04), Cloudcover(-.37), Percipitation (-.23) all have a negative correlation.
## Q6 What season seems to be least popular for trail users? Fall is the least popular season for trailusers(-.25).

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.

No the correlation between high temp and cloudcover is very small.The correlation between the two is (-0.1).

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. High temp and cloudcover are not related. All of the points are spread out, only two points were connected (-.01).

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.