Plotting Options
Request a plot by choosing from the plotting options in the pull-down menu, filling in labels in the text boxes, and placing the numbers to be plotted in the large box at the bottom of the page.
For a histogram, enter a single number per line in the large box. For a y-versus-x plot, enter both an x and then a y value on each line, and for a y-versus-x plot with associated errors, enter an x and a y value and then an associated error on each line, separating the numbers on each line with white space (blanks).
Do not, for example, enter all of your x values on one line, followed by all of your y values on the next line. Enter pairs of x and y values on each line instead.
Be careful when entering your data. Do not leave blank lines, or add extra entries to the lines that contain the numbers to be plotted.
- If you want to start out by plotting some existing sample data, you can recreate any of the three sample plots shown under Examples.
- If you want to calculate the mean value and standard deviation for a set of points but don't actually need to plot them as a histogram, just type the values into the box labeled "numbers to plot". The mean (average) value and the standard deviation for the points will appear just above the box. You do not need to fill in your name and access code or define any of the plot labels in order to use this option.
- You might occasionally want to invert an axis to run from large values to small rather than from small to large, if you plot the brightness of an object in units of magnitudes for example. (Recall that the magnitude scale is defined so that objects with larger magnitudes are actually fainter than those with smaller magnitudes.) Most of the time, however, you should not need to invert either axis.
- If you are plotting the relationship between x and and y, you will usually want to add a linear fit (showing the best-fit straight line which attempts to pass as closely as possible to all of the points). You may, however, elect to hide this line.
- You can require that this best-fit line passes through the origin.