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 largest group of individuals who have Alzheimers are non-smokers who smoke zero 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.

The group that has more cases than expected given independence are the individuals who smoke greater than 20 cigarettes per day and have dimentia because that is the group

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

Even though there are more cases of people with Alzheimers who do not smoke, there was not a high Pearson residual, so there is not enough evidence to conclude a strong relationship between number of cigarettes and having Alzheimers. One way to test this correlation could be through a scatter plot.

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)?

volume/ hightemp, lowtemp, avgtemp, and summer

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

Summer, there is the strongest correlation between volume and this season. The weather is the nicest therefore more people would want to use 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? 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 analyzing the scatterplot, there seems to be no strong correlation between cloudcover and high temp. The points of data are completely scattered with no signs of a positive or negative relationship.

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.