Final answer:
The question is related to performing a Principal Component Analysis (PCA) using R-code on selected variables. You need to pre-process data, select the required variables, and run the PCA using functions like prcomp or PCA from the FactoMineR package.
Step-by-step explanation:
The student is asking how to perform a Principal Component Analysis (PCA) on selected variables using R-code. This typically involves the steps of data pre-processing, selecting the variables of interest, running the PCA function, and interpreting the results.
To run PCA on specific variables in R, you might use the prcomp or PCA functions (the latter available in the FactoMineR package). One would typically start by standardizing the data if required, then selecting the subset of variables for PCA, followed by executing the PCA function and extracting the results for analysis.
Here's a simple example using the prcomp function:
my_data <- my_dataframe[, c("var1", "var2", "var3")] # select specific variables
summary(pca_results): # View a summary of the PCA results