Table of Contents

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subset.4<-subset(dataframe, x < 5) #subset of the whole dataframe where x < 5
subset.4<-subset(dataframe, x == 5) #subset of the whole dataframe where x = 5

• create a subset of sim.alspac for males called subset.male and for females called subset.female
• How many participants are female and how many are male? HINT: Use dim to check the dimensions of subset.male and subset.female.  

Changing class

• The data dictionary tells us that the variable male is categorical.  Check the class of male using the class function.

Exploring the data

• Get object summary statistics by using the summary function on subset.male and subset.female
• Use the boxplot function to plot BMI at age 7 against gender. HINT: You will only need to use the arguments formula= and data=
• Use the hist function to plot histograms of BMI age 7 for females and males.  HINT: You can layer graphs over one another by using the argument add=T in the second histogram.  Line colour of the histogram can be set using the argument e.g. border="red"
• Make the plot more readable by using the legend to add an appropriate key.
• Output your graph as a .png file using the png function. 

Modelling

Rounding numbers

signif(x, digits = 6)

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