This document provides solutions to exercises on descriptive statistics using RStudio, focusing on the heritability of height based on Galton's dataset.
Extract
[...] 200.7 44.67919 6.684249 Represent the size of girls and boys separately using histograms, boxplots. # Histograms Solution: Solution: hist(galton$height[galton$sex xlab = "Height in ylab = "Frequency"," main = "Distribution of heights among girls"," xlim = range(galton$height) + col="red")" hist(galton$height[galton$sex xlab = "Height in cm" ylab = "Frequency"" main = "Distribution of heights among boys"" xlim = range(galton$height) + col="blue")" Result in R : Result in R : # Boxplots Solution: Result in R : boxplot(galton$height ~ galton$sex, xlab = ylab = "Height in cm" main = "Distribution of heights by sex"" names = c("Girls", "Boys") col = Produce a scatterplot ("cloud of points") to see the height of children in relation to the average height of parents. [...]
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[...] Introduction to descriptive statistics - Heritability statistics on RStudio Assignment 1 Exercise 1 The file galton.txt contains a classic dataset on the heritability of height in man. It was collected by Francis Galton, who was a cousin of Darwin. Import the data. Solution: Using the menu File ? Import Dataset ? From text (base)? generates this code: galton read.delim("C:/Users/Desktop/galton.txt") # Path to the file on the PC View(galton) # Visualization of the imported file Provide descriptive statistics for the size of children for all children, for girls and boys separately. [...]
[...] Solution: length(galton$sex[galton$sex & galton$height > galton$father]) Result in Interpretation of results : 231 In the dataset boys are taller than their father. Exercise 2 The file parents.txt contains the data of the parents extracted from the file galton.txt. Import the file. Solution: In using the menu File ? Import Dataset ? From text (base)? generates this code: parents read.delim("C:/Users/Desktop/parents.txt") # Path to the file on the PC View(parents) # Visualisation of the imported file Create a graph that shows the mother's size in relation to the father's size. [...]
[...] Median Mean 3rd Qu. Max. 200.7 82.82116 9.100613 # Descriptive statistics of the size of girls Solution: Result in summary(galton$height[galton$sex # stats var(galton$height[galton$sex # variance sd(galton$height[galton$sex # standard deviation Min. 1st Qu. Median Mean 3rd Qu. Max. 179.1 36.24777 6.020612 # Descriptive statistics of the height of boys Solution: Result in summary(galton$height[galton$sex # stats var(galton$height[galton$sex # variance sd(galton$height[galton$sex # standard deviation Min. 1st Qu. Median Mean 3rd Qu. [...]
