R Markdown
rm(list=ls())
3.1
## [1] 3.1
#Import dataset
dat4<-read.csv("D:/Users/cse/Downloads/dat4.csv")
head(dat4)
attach(dat4)
Company=as.factor(Company)
str(dat4)
## 'data.frame': 100 obs. of 3 variables:
## $ ID : int 1 2 3 4 5 6 7 8 9 10 ...
## $ Company : chr "A" "A" "A" "A" ...
## $ Concentration: num 101.1 100 101.4 102.9 99.8 ...
summary(dat4)
## ID Company Concentration
## Min. : 1.00 Length:100 Min. : 96.02
## 1st Qu.: 25.75 Class :character 1st Qu.: 98.89
## Median : 50.50 Mode :character Median : 99.98
## Mean : 50.50 Mean :100.02
## 3rd Qu.: 75.25 3rd Qu.:101.17
## Max. :100.00 Max. :103.97
sd(dat4$Concentration)
## [1] 1.797305
3.2
## [1] 3.2
# Histogram of concentrations
hist(Concentration, main="Distribution of Tablet Concentrations", xlab ="Concentration(mg)")
# Boxplot by company
boxplot(Concentration~Company,data=dat4,main="Tablet Concentrations by Company",xlab = "Company",ylab="Concentration (mg)")
min=min(dat4$concentration)
## Warning in min(dat4$concentration): no non-missing arguments to min; returning
## Inf
max=max(dat4$Concentration)
Q1=98.89
Q3=101.17
Q3-Q1
## [1] 2.28
max-min
## [1] -Inf
3.3
## [1] 3.3
t.test(Concentration, mu=100)
##
## One Sample t-test
##
## data: Concentration
## t = 0.099037, df = 99, p-value = 0.9213
## alternative hypothesis: true mean is not equal to 100
## 95 percent confidence interval:
## 99.66118 100.37442
## sample estimates:
## mean of x
## 100.0178
3.4
## [1] 3.4
#Company A vs Company B
t.test(Concentration~Company,data=subset(dat4,Company %in%c("A","B")))
##
## Welch Two Sample t-test
##
## data: Concentration by Company
## t = 1.9312, df = 64.692, p-value = 0.05784
## alternative hypothesis: true difference in means between group A and group B is not equal to 0
## 95 percent confidence interval:
## -0.02577558 1.53172923
## sample estimates:
## mean in group A mean in group B
## 99.91176 99.15879
3.5
## [1] 3.5
# Perform ANOVA
anova_model <-aov(Concentration~Company,data=dat4)
#Display ANOVA table
summary(anova_model)
## Df Sum Sq Mean Sq F value Pr(>F)
## Company 2 55.67 27.836 10.22 9.36e-05 ***
## Residuals 97 264.13 2.723
## ---
## Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1