Digitalis and Calcium Uptake A study was conducted to compare the effects of three levels of digitalis on the levels of calcium in the heart muscles of dogs. Because general level of calcium uptake varies from one animal to another, the tissue for a heart muscle was regarded as a block, and comparisons of the three digitalis levels (treatments) were made within a given animal. The calcium uptakes for the three levels of digitalis, A, B, and C, were compared based on the heart muscles of four dogs and the results are given in the table. Use the MINITAB printout to answer the questions.
Dogs |
1 | 2 | 3 | 4 |
A | C | B | A |
1342 | 1698 | 1296 | 1150 |
B | B | A | C |
1608 | 1387 | 1029 | 1579 |
C | A | C | B |
1881 | 1140 | 1549 | 1319 |
a. How many degrees of freedom are associated with SSE?
b. Do the data present sufficient evidence to indicate a difference in the mean uptakes of calcium for the three levels of digitalis?
c. Use Tukey’s method of paired comparisons with a = .01 to rank the mean calcium uptakes for the three levels of digitalis.
d. Do the data indicate a difference in the mean uptakes of calcium for the four heart muscles?
e. Use Tukey’s method of paired comparisons with a = .01 to rank the mean calcium uptakes for the heart muscles of the four dogs used in the experiment. Are these results of any practical value to the researcher?
f. Give the standard error of the difference between the mean calcium uptakes for two levels of digitalis.
g. Find a 95% confidence interval for the difference in mean responses between treatments A and B.
MINITAB output for Exercise
Two-way ANOVA: Uptake versus Digitalis, Dog