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”.

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

The smallest group that has Other dementias are the group that smokes less than 10 cigarettes a day. The other group smokes over 20 cigarettes a day that has the next largest amount of dementias.

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

Other diagnoses of other cases have a large amount of people who smoke 10-20 packs a day.

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

Smoking does seem to matter in determining Alzheimers. Other diagnoses are also affected by cigarretts a lot as well, more so in some cases.

Q4 Create correlation plot for SaratogaHouses.

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

Q5 What variable has the strongest positive correlation with home prices (price)?

Living area has the highest correlation with home price.

Q6 Based on your answer in Q5, what type of homes would be more expensive?

Houses with the most living area would be the most expensive.

Q7 The correlation coefficient between lotSize and pctCollege 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.

There is probably not much of a correlation between the two. The lot size and pctCollege probably don’t have much to do with each other.

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.

They are in fact related, they both have a positive correlation between each other.

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.