Mary wishes to assess whether vitamin C is effective in treatment of colds. To measure her hypothesis she decides to conduct the 2-year experimental study. She obtains 30 volunteers from the undergraduate class to participate. She randomly assigns the equal number of students to three groups: placebo (group 1), low doses of vitamin C (group 2), and high doses of vitamin C (group 3). In first and second year of study, students in all three groups are monitored to measure the number of days that they have cold symptoms. throughout the first year students don't take any pills. In the second year of study, students take pills which contain one of following: no active ingredients (group 1), low doses of vitamin c (group 2), or high doses of vitamin c (group 3). An  excel data file (excel for prob 34 Vitamins) comprises 30 cases you must use to examine the impact of vitamin C.

Conduct appropriate statistical test to see if there're any differences between the groups and find out if vitamin C is effective in treatment of colds.