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 Alzheimer. Discuss it by number of cigarettes per day.

The group that has the largest amount of Alzheimers is the group who does not smoke. We can tell this because the none box is the largest in the Alzheimers box.

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

The only group who has more cases than expected given independence is the other dementias group who smokes more than 20 cigarettes a day. We can see this because this is the only box that is blue.

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

Smoking does not seem to matter more in determining Alzheimers because the group in Alzheimers that has the largest amount is the group who does not smoke. We can tell this because people who do smoke still have Alzheimers but not as large as someone who doesn’t.

Q4 Create correlation plot for RailTrail.

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

Q5 What variables have positve correlation with the number of trail users (volume)?

The variables that have a positive correlation with volume are hightemp, avgtemp, lowtemp, and summer.

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

The season that seems to be the most popular for trail users is the summer with an average temperature. You can tell this because between summer and fall the summer has positive correlations while fall has all negative correlations.

Q7 The correlation coefficient between hightemp and cloudcover is quite small. Would you be sure that the two variables are not related at all? 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.

There is no correlation between the variables, you can see this because in the scatterplot they do not form any linear shape and are spread out completely.

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.