4.1     matplotlib is a powerful graphing package for Python that can draw histograms, bar charts, scatterplots, and many other kinds of graphs. It is particularly useful if you are taking a science course in which you need to graph and analyze data. You can read about and download matplotlib for your computer at https://matplotlib.org. Read the documentation to learn how to use this module to plot a histogram of the data shown in this chapter.

4.2     Given a list of points of the form [(x₁, y₁), (x₂, y₂), ..., (x_n, y_n)], write a function called plotRegression that accepts a list as a parameter and uses a turtle to plot those points and a best-fit line according to the following formulas:

where is the mean of the x values, is the mean of the y values, and n is the number of points. The Greek letter represents the sum operation. For example, indicates the addition of all the x values.

Your program should analyze the points and correctly scale the window using setworldcoordinates so that each point can be plotted. You should then draw the best-fit line in a different color through the points.

4.3     Have you ever tried to talk like a pirate? Write a function, toPirate, that takes an English sentence in the form of a string as a parameter. The toPirate function should return a string containing the pirate translation of your sentence. Use the following table to construct a translation dictionary. You can also consult an online website for more pirate phrases.

4.4     Now try an even more challenging exercise: Translate two-word phrases into their pirate equivalents. For example, the two-word phrase “excuse me” would be translated into simply “arrrr.”