Adding function for computation and plotting of data.

[ASDelaney]

Subject: Enhancement Request - Add Analysis and Visualization Features

Description:
Enhancement to the existing script by adding a new method (compute_analysis) and related functionality to compute and visualize the average word count of articles in the dataset. Additionally, a new method (plot_data) has been introduced to generate a bar chart visualizing the word counts.

Proposed Changes:
New Method: compute_analysis

Purpose: Compute the average word count of articles in the dataset.
Steps:
Extract word counts from the dataset.
Calculate the average word count.
Visualize word counts with a bar chart.
Save the plot as an image (optional).
Exception Handling: Raise an error if data is not loaded.
New Method: plot_data

Purpose: Generate a bar chart of word counts.
Parameters:
word_counts: List of word counts.
save_path (optional): Path to save the plot image.
Steps:
Create a bar chart.
Set labels and title.
Save the plot if save_path is provided (optional).
Display the plot (optional).
Notify Done: