DASI_PROJECT_PROPOSAL

1.txt

Empty_test_file

DASI_Project_Proposal.Rmd

---
title: "DASI_Project_proposal"
author: "myself_vinsent"
date: "Saturday, September 20, 2014"
output: html_document
---

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### Introduction:

This study on dataset esoph data set to find the relation between age group, type of cancer causing agent(Alcohol and Tobacco). from the R- dataset.
this dataset contains 88 observation of control and ncases.

### Data:
```{r}
summary(esoph)
```



### Exploratory data analysis:
```{r, echo=FALSE}
plot(esoph)

## effects of alcohol, tobacco and interaction, age-adjusted
model1 <- glm(cbind(ncases, ncontrols) ~ agegp + tobgp * alcgp,
              data = esoph, family = binomial())

## Try a linear effect of alcohol and tobacco
model2 <- glm(cbind(ncases, ncontrols) ~ agegp + unclass(tobgp)
              + unclass(alcgp),
              data = esoph, family = binomial())

plot(model1)
anova(model1,model2)
```

### Inference:
#### Calculate the cancer proportion by alcohol and tobacco usage


```{r echo = FALSE, ggplot2ex}
library(plyr)
library(reshape2)
df <- esoph 

CancerProportion <- function(df) {  
     cancer.prop <- sum(df$ncases) / sum(df$ncontrols)  
     data.frame(cancer.prop=cancer.prop)  
   }
##SPLIT by the tobgp column  
# APPLY this function to each tobacco group  

alc.tob.cancer <- ddply(esoph, .(alcgp, tobgp), CancerProportion)

head(alc.tob.cancer)  
library(lattice)
library(ggplot2)
 g <- qplot(x=alcgp, y=tobgp, fill=log(cancer.prop), geom='tile', data=alc.tob.cancer ,labs(x='Alcohol consumption', y='Tobacco Consumption',  title='Cancer by Alcohol and Tobacco'))

plot(g)

```

#### The cancer caused by both tobaco and Alcohol are plotted in a log ratio,
####the inverse log , the color are the fill is consider as cancer.prop <- sum(df$ncases) / sum(df$ncontrols)( this states a ratio between affected persons to  healthy living) 

### Conclusion:

####A high number of case in age group 30+ can be seen in log plot. for both Alcohol and Tobaco consumption.


###Reference
http://davetsao.com/blog/2013-07-28-useful-r-packages.html