Create a Jupyter Notebook (.ipynb file) named "YourFileName" and complete the following tasks:
1. Import the pandas library and read a dataset named "data.csv" into a DataFrame. Display the first 5 rows of the DataFrame.
2. Plot a bar chart using the matplotlib.pyplot library to visualize the distribution of a categorical variable in the dataset. Provide appropriate labels and title for the chart.
3. Perform basic statistical analysis on a numerical column in the dataset using the describe() function from pandas. Interpret the results.
4. Create a new column in the DataFrame by performing a transformation on an existing column (e.g., calculate the logarithm). Display the updated DataFrame.