Healthy cereal? Researchers collected data on $77$ brands of cereal at a local supermarket.$25$ For each brand, the sugar content (grams per serving) and the shelf in the store on which the cereal was located ($1$ = bottom, $2$ = middle, $3$ = top) were recorded. A dot-plot of the data is shown below. Compare the three distributions. Critics claim that supermarkets tend to put sugary kids’ cereals on lower shelves, where the kids can see them. Do the data from this study support this claim?

The sugar level for the middle shelf is higher. The bottom shelf contains mostly low sugar levels.

Dot plots are one of the most fundamental statistical plots, and they work best with small to medium-sized data sets.

Because the distribution $3$is skewed to the right, cereal brands with less sugar are kept on the top shelf in $36$of the $77$local stores. The distribution $2$is skewed to the left, indicating that high-sugar-coated cereals are kept on the Centre shelf at $21$of the $77$supermarkets in the area. And distribution 1 is biased to the left once more, indicating that cereals with a high sugar coat are kept on the bottom shelf in $20$of the $77$supermarkets in the area. All of the distributions are one-dimensional. The ranges of all three distributions are roughly identical. Because the distribution $1$for cereals on the bottom shelf is skewed to the right, many local supermarkets put fewer sugary cereals on the bottom shelf. As a result, the dot-plot distribution partially supports the claim that supermarkets place sugary kids' cereals on lower shelves where the kids can see them. The smoothness to the left in Distribution $2$indicates that many local retailers have more sweet cereals on the middle shelf. The assumption appears to be correct because the sugar levels on the middle shelf are higher (more dots are to the right than for the bottom and upper shelf).