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 that has alzheimers does not smoke, this is shown because in the alzheimers chunk of the graph, the group under ‘none’ is a larger chunk of the graph than those that do smoke x number of cigarettes a 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 is those with dementia that smoke more than 20 cigarettes a day. This is by chance as shown by the color of the chunk (purple, while the rest are grey).

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

Smoking does not seem to matter when determining alzheimers because the largest group of people with alzheimers did not smoke at all, but there were still some, so there does not seem to be any correlation.

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 witth a positive correlation with the number of trail users, represented in the table as ‘volume’, are hightemp, avgtemp, lowtemp, and summer. The numbers shown for these correlations are all positive numbers.

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

The season that seems to be the most popular for trail users is summer because it has the highest positive correlation with volume at 0.23, while the correlation with fall is -0.25.

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

To be sure the variables are not related at all you need to create a scatter plot.

The scatter plot shows that the two variables are note related because there is no linear relationship, the data in the scatter plot is scattered all over the chart.

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.