# R homework

#### Jesmin

##### New Member
1. Fit appropriate regression models to describe relationship between the variables X and Y using the following three data sets separately. Use Y as the response and X as the explanatory variable. You must show all the necessary tables and fi gures for the model fi t and also comment on the fi t.

Table 1: Data Set - A
$$\begin{tabular}{|l |r|} \hline X & Y \\ \hline 32 & 48.5 \\ 36.3 & 42.9 \\ 36.5 & 32.6 \\ 34 & 38.4 \\ 27.1 & 27.6 \\ 45.8 & 75.8 \\ \hline \end{tabular}$$

Table 2: Data Set - B
$$\begin{tabular}{|l |r|} \hline X & Y \\ \hline 60.5 & 5457.6 \\ 56.5 & 4755.2 \\ 48 & 3430.3 \\ 53.1 & 4203.9 \\ 57.1 & 2754.6 \\ 25.8 & 7005.8 \\ 12 & 6666 \\ \hline \end{tabular}$$

Table 3: Data Set - C
$$\begin{tabular}{|l |r|} \hline X & Y \\ \hline 24.2 & 148.5 \\ 32.5 & 422.9 \\ 10.4 & 328.6 \\ 29.1 & 658.4 \\ 27.1 & 2796.6 \\ \hline \end{tabular}$$

I have tried this as :
Code:
set1 <- read.table("G:\\data1.txt",header=TRUE) # Data set A
regr1 <- lm(Y~X,data=set1)
regr1
with(set1,plot(Y~X,xlab="explanatory variable X",ylab="response variable Y",
main="Relationship between X & Y of data set1"))

regr2 <- lm(Y~X,data=set2)
regr2
with(set2,plot(Y~X,xlab="explanatory variable X",ylab="response variable Y",
main="Relationship between X & Y of data set2"))

regr3 <- lm(Y~X,data=set3)
regr3
with(set3,plot(Y~X,xlab="explanatory variable X",ylab="response variable Y",
main="Relationship between X & Y of data set3"))
Are these sufficient according to question or i have to add more information to show the relationship of X & Y since i have been asked to show all the necessary tables and fi gures for the model fi t and also comment on the fit.

The 2nd part of the question is:
Combine the three data sets (from question 1) into a R data object data.frame of the following type:
$$\begin{tabular}{|l c r|} \hline X & Y & Type \\ \hline 32 & 48.5 & A \\ 36.3 & 42.9 & A \\ \vdots 45.8 & 75.8 & A \\ 60.5 & 5457.6 & B \\ \vdots 12 & 6666 & B \\ 24.2 & 48.5 & C \\ \vdots 271 & 2796.6 & C \\ \hline \end{tabular}$$

I couldn't add new column "Type". But tried to add this by "within"
Code:
datABC <- rbind(set1,set2,set3)
within(datABC,Type={})