Bar Graph (Stat Plot)

Find the mean and standard deviation of a list of numbers.

Complete Code

POD for Macro Files

PG problem file

Explanation

DOCUMENT();

loadMacros(
    'PGstandard.pl',       'PGML.pl',
    'StatisticalPlots.pl', 'contextPercent.pl',
    'PGcourse.pl'
);

Preamble

This is a updated version of Bar Graph to use the StatisticalPlots.pl macro, which provides some convenience methods for creating Statistical plots. This also uses the contextPercent.pl to provide the Percent context.

Context('Percent');

@grades = map { random(1, 5) } (0 .. 3);

$statPlot = StatPlot(
    xmin            => 0,
    xmax            => 5,
    xtick_delta     => 1,
    xminor          => 0,
    ymin            => 0,
    ymax            => 6,
    yminor          => 0,
    ytick_delta     => 1,
    xtick_labels    => { 1 => 'A', 2 => 'B', 3 => 'C', 4 => 'D' },
    show_grid       => 0,
    rounded_corners => 1
);

$statPlot->add_barplot(
    [ 1 .. 4 ], ~~@grades,
    fill_colors  => [ 'Red,', 'Salmon', 'LightYellow', 'LightGreen' ],
    stroke_width => 1,
    bar_width    => 0.9
);

$alt_text =
    "A bar graph with vertical bars.  The height of the bar labelled A "
    . "is $grades[0]. The height of the bar labelled B is $grades[1].  "
    . " The height of the bar labelled C is $grades[2] and finally the "
    . "bar labelled D is $grades[3].";

# This code adds up all the numbers in the @grades array.
$num_students = 0;
$num_students += $_ for @grades;

$perA = Compute($grades[0] / $num_students);

Setup

The ‘Percent’ context allow students to enter percents.

To create a graph, start with a StatPlot. The min and max options in the two directions give the bounding box of the plot. The tick_delta for each direction gives the distance between tick marks and the minor option is the number of minor ticks between each tick.

Use xtick_labels to customize the tick labels. The hash reference value is a mapping from tick positions to new labels.

The bars are added with the add_barplot method passing the x and y data values. The bar_width gives the relative width of the bar. If this option is 1, then there is no gap between bars. See StatisticalPlots.pl for other options to this method.

Make sure that an alternate text is added to all graphs for accessibility. Be detailed.

BEGIN_PGML
The following is a distribution of grades on a Statistics quiz.
>>[! [$alt_text] !]{$statPlot}{400}<<

What percentage of students earned an A? [_]{$perA}
END_PGML

Statement

In this case, we plot the bar graph and ask a question. Since the context is Percent, the students can answer the question with either a fraction, decimal or percent. If only percent answers is desired, see the flags for the Percent context in the macro.

BEGIN_PGML_SOLUTION
The total number of students that took the quiz is [$total] so the percentage is
the number of A students or [`[$grades[0]]/[$num_students] = [$perA] `]
END_PGML_SOLUTION

ENDDOCUMENT();

Solution

A solution should be provided here.