Interactive Statistics

3.25) A group of 40 adults who suffer from severe migraines were asked to take a dose of vitamin B each day. After a period of two years, 28 of the adults reported that their migraines were less severe. From this information alone you can conclude (select one) (a) vitamin B is effective in reducing the severity of migraines. (b) nothing, because two years is too short of a period of time. (c) nothing, because two years is too long of a period of time. (d) nothing, because there is no control group for comparison