On page 22 of the slide, the 1D array is [1, 1, 1, 1, 1], but the dots are uneven. Then why their values are the same? What's the value of the point that the arrow is pointing at? Though it gives Moving average in 1D: [1, 1, 1, 1, 1]/5, what exactly is that value?
The illustration is showing your data (labelled as "original") and the result of convolving your moving average filter with your data (labelled as "smoothed"). The filter/kernel is [1 1 1 1 1]/5 and gives each of the five samples equal weight. Effectively, it takes the average of the five samples it overlaps with during each step of the convolution process. It can also be written as [0.2 0.2 0.2 0.2 0.2] or [1/5 1/5 1/5 1/5 1/5]. The values in this filter are the same, but you can also choose different values depending on what you wish to accomplish. In the next slide, they give the filter [1 4 6 4 1]/16. This filter gives more weight or importance to the samples that are near the center of the filter.
I hope this helps.