1. Barium137m is a radioactive form of the element barium that decays very rapidly. It is easy and safe to use for lab experiments in schools and colleges. In a typical experiment, the radioactivity of a sample of barium137m is measured for one minute. It is then measured for three additional one-minute periods, separated by two minutes. Thus, data are recorded at one, three, ve, and seven minutes after the start of the rst counting period. The measurement units are counts. Here are the data for one of these experiments: Time 1 3 5 7 Count 1 578 317 203 118 (a) Plot the data in a scatterplot and label the graph appropriately. Which one is the explanatory variable and which one is the response variable? Explain your reasoning. (b) Describe the form, direction, and strength of the relationship based on the scatterplot. (0) Calculate the correlation coeicient between time and count, rounding to 3 decimal places. Is it a good measure to describe the relationship between the two variables? Why or why not