Instruction: Provide a detailed explanation of the 'crosstab' function in Pandas, including its syntax, parameters, and a practical example of its usage in data analysis.
Context: This question assesses the candidate's understanding of specialized data analysis functions in Pandas. The 'crosstab' function is crucial for summarizing and analyzing data, making it essential for roles that require deep insights into categorical data. Candidates should demonstrate their ability to effectively use 'crosstab' to facilitate data comparison or trend identification.