ry(dataMaid)

#Load data
data(presiData)

#Copy data. This is the data we will make changes to.
pd &lt;- presiData


#We fix the following mistake:
#The variables firstName and lastName are stored using a non-standard
#class even though they are really just character variables.
class(pd$firstName) &lt;- &quot;character&quot;
class(pd$lastName) &lt;- &quot;character&quot;

#We fix the following mistake: 
#Aragorn Arathornson is included in the dataset.
pd &lt;- pd[!(pd$firstName == &quot;Aragorn&quot; &amp; 