ITBAL-3 on Jan 22

Question 1: 

Fit ‘lm’ and comment on the applicability of ‘lm’

Plot1: Residual vs Independent curve

Plot2: Standard Residual vs independent curve

Command:

data<-read.csv(file.choose(),header=T)

data

x<-data$groove

x

y<-data$mileage

y

reg<-lm(y~x)

res<-resid(reg)

res

plot(x,res)

a) Grooves vs Mileage data:

The plot is parabolic.
So, regression is not possible.

b) Alpha-Pluto data:

A Random plot.
Implies, regression can be applied.


Command:
qqnorm(res)
qqline(res)

Question 2: Justify Null hypothesis for ANOVA

Command:

data<-read.csv(file.choose(),header=T)

data

data.anova<-aov(data$comfort.levels~data$chair1)

summary(data.anova)