time a bag of chips remains fresh on the grocery shelf. A random sample of potato chips with the old design of the bag was compared to a random sample of potato chips with the new bag. Summary statistics pertaining to the number of days the chips remained fresh are given below. At a 95% level of confidence (α = .05), the company wishes to investigate if the new bag has an increased freshness time over the old bag.
New Bag Old Bag
(Sample #1) (Sample #2)
Sample Mean 21.2 days 20.8 days
Sample Standard Deviation 2.5 days 2.8 days
Sample Size 45 50
What is the correct Null and Alternate Hypothesis?
a. H_0: \mu_d>0\;\; H_1: \mu_d < 0
b. H_0: \mu_1>\mu_2 \;\;H_1:\mu_1 \leq \mu_2
c. H_0: \mu_d =0\;\; H_1: \mu_d < 0
d. H_0: \mu_1\leq\mu_2 \;\;H_1:\mu_1 > \mu_2