Final answer:
A researcher graphing data to show colleagues is using descriptive statistics, as it involves summarizing data directly observed or collected, without making predictions or testing hypotheses.
Step-by-step explanation:
When a researcher makes a graph of her data to show her colleagues, she is utilizing descriptive statistics. Descriptive statistics involve organizing and summarizing data, which can be done through graphical representations like bar graphs, line charts, and pie charts, or through numerical methods such as calculating the average (mean), median, or mode.
In the example given, if the scientist is determining the average decrease in tumor size for the drug-treated group, this is an instance of descriptive statistics, as the average is a way of summarizing the data. Inferential statistics, on the other hand, would be used if the researcher wanted to interpret the data to test hypotheses or to determine how likely it is that the observed results are due to chance rather than a specific cause.
Exploratory statistics and predictive statistics are not standard terms widely recognized in the field of statistics, hence they are not applicable to this scenario.