Dianne wants to see if the average number of steps she takes per day is higher this year than it was last year. She takes random sample of 42 days from this year and records how many steps she took during those days. She knows that the population standard deviation of the number of steps is about 50 steps . If Dianne walked an average of 8420 steps per day last year, what hypothesis would she use to check if she averaged higher than this year? A. One mean sigma unknown B. One mean sigma known C. The mean differences using dependent samples(paired data) D. The difference of means using independent samples. E. ANOVA