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### EXERCISE 2.1
################
### Consider you want to buy apples for producing pies.
### You can decide between apples from three different
### plantations, A, B & C.
### Compare the apple characteristics from a sample
### of each plantation using descriptive statistics
### and graphical representations.
### The study data is available as EXCEL file.
### To import the data start as follows:

### Store the study data at a new folder on your PC.
### Install the R-package "xlsx".
### Setting, Packages & Data Import
setwd("C:\\...\\DataExamples")
library(xlsx)
X = read.xlsx("Apples.xlsx", sheetIndex=1)


################
### EXERCISE 2.2
################
### Determine absolute and relative frequencies
### for the qualitative apple characteristics
### using the R-functions, table, prop.table.
### To obtain separate results per plantation,
### you can employ the function tapply.
### Summarize your results in one table in WORD document.
### Example:
t(round(100 * prop.table(table(X$Plantation, X$Condition), 1), 1))

################
### EXERCISE 2.3
################
### Summarize the metric data per plantation
### using the R-functions mean, sd, min, max, median.
### Add the results to your summary table in WORD.
### Example:
round(tapply(X$Weight, X$Plantation, mean), 1)


################
### EXERCISE 2.4
################
### Illustrate the data using the R-functions
### barplot and boxplot.
### Add the figures to your WORD report.
### Examples:
barplot(table(X$Condition, X$Plantation), cex.lab=1.5, cex.axis=1.5, main="Condition", cex.main=1.5, ylim=c(0, 180), xlab="Plantation", ylab="Absolute Frequency", col=c("lightgrey", "grey"), cex.names=1.5)
boxplot(X$Weight ~ X$Plantation, cex.axis=1.5, cex.lab=1.5, xlab="Plantation", ylab="Weight (g)")


################
### EXERCISE 2.5
################
### Compare your analysis code and WORD-report
### with the archetype analysis provided during
### the course by your tutor.


################
### EXERCISE 2.6
################
### Based on the statistical analysis,
### discuss within the group from which plantation
### you would buy the apples for your production.