The goal of making a scatter plot is to visually identify the type of relationship between two quantitative variables quickly. To explore whether a scatter plot can achieve this goal when it is made in the form of a tactile graph and presented to blind people, we conducted an experiment in which x-y data sets were presented to blind participants in three data representations: tactile graph, tactile table, and electronic table, and the participants were asked to identify the type of relationship between two variables. Under all presentation conditions, eight participants or more achieved 100% correct rate. Tactile graphs were understood with the shortest time, tactile tables with the second shortest, and electronic tables needed the longest time. This time differences were due to the different strategies for identifying the relationships. Both tactile graph and tactile table conditions gained significantly higher subjective ratings than the electronic table condition. These results show the usefulness of tactile scatter plots for blind people although it is limited to the present experimental condition.