this is probabilty homework

Question 1 (5 marks) Four treatments for fever blisters, including a placebo (A), were randomly assigned to 20 patients. The data below show, for each treatment, the numbers of days from initial appearance of the blisters until healing is complete. Treatment Number of days 5 8 7 78 46 635 64 454 74665 Test the hypothesis, at the 5% significance level, that there is no difference between the four treatments with respect to mean time of healing