Final answer:
A rating mark placed in an interval on a graph represents the count of data points within that range. It indicates frequencies on an interval scale and, on a ratio scale, allows for meaningful zero points and ratio calculations. The placement of marks also follows specific conventions when constructing histograms.
Step-by-step explanation:
Placing a rating mark in an interval on a graph or chart indicates the frequency or count of data points that fall within that particular range. When data is measured on an interval scale, differences between data points can be meaningfully calculated, and if the data is on a ratio scale, it also has a meaningful zero point and allows for the calculation of ratios. For example, in a histogram that represents test scores, if the interval 50-56.5 has a rating mark placed at its midpoint, it showcases the number of students who scored within that range. Furthermore, when constructing histograms, it is common practice that a value is counted in a class interval if it falls on the left boundary but not if it falls on the right boundary, though different researchers may select different methods for creating histograms.