# Question

The following data are from Gennings, Chinchilli, and Carter, (1989). An in vitro toxicity study of isolated hepatocyte suspensions was conducted to study the impact of combining carbon tetrachloride (CCl4) and chloroform (CHCl3) on the toxicity of cells. Cell toxicity was measured by the amount oflactic dehydrogenase (LDH) enzyme leakage. The study involved randomly assigning four flasks to each of the 16 treatments obtained by combining four levels of CCl4 (0, 1.0, 2.5, and 5.0 mM) with four levels of CHCl3 (0, 5, 10, and 25 mM). The percentage of LDH leakage from the cells in each of the 64 flasks was measured just prior to applying the treatment to the flasks and at .01, .25, .5, 1, 2, and 3 hours after applying the treatment. The percentages of LDH leakage are given in the following table.

a. Plot the mean percentages of LDH leakage by time for the 16 treatments. Does there appear to be an effect due to increasing the level of CCl4 or CHCl3?

b. From the plot, does there appear to be an increase in the mean percentages of leakage as time after treatment increases?

c. Plot a profile plot of the mean percentage of LDH leakage separately for each time period. Does there appear to be a difference in the profile plots?

a. Plot the mean percentages of LDH leakage by time for the 16 treatments. Does there appear to be an effect due to increasing the level of CCl4 or CHCl3?

b. From the plot, does there appear to be an increase in the mean percentages of leakage as time after treatment increases?

c. Plot a profile plot of the mean percentage of LDH leakage separately for each time period. Does there appear to be a difference in the profile plots?

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