Instruction: Demonstrate how to perform a complex data transformation using dplyr, including filtering, selecting, and summarizing data.
Context: This question evaluates the candidate's proficiency with the dplyr package for data manipulation, an essential skill for efficient data analysis in R.
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First, let's clarify our task. We aim to utilize dplyr to filter, select, and summarize data - a common yet critical operation in data analysis. My approach here is structured yet adaptable, ensuring you can tailor it to various data sets and requirements.
To begin, let's assume we're working with a dataset sales_data that contains several years of sales information across multiple stores, including columns for store_id, year, month, product_category, and sales_amount. Our objective is to summarize the total sales by year and product category, but only for a specific store and only...