A pharmaceutical company wants to find out whether there is any difference between three different types of drugs (A, B and C ) with respect to how long they're retained in body. Fifteen people are randomly assigned - five to each drug. Data are gathered on number of days the drug remains in the body before no trace of drug is found. The data from such tests are reported in table below. Are there differences among these three drugs with respect to how long they're retained in the body? Employ a level of significance of 0.01.
Days in the body