DHL Shipping claims that it ships 95% of its orders within three working days. You select a simple random sample of 100 orders and discover that only 91 of them shipped on time.

a) If DHL really does ship 95% on time, what is the probability that the company shipped 91 or fewer out of 100 orders were shipped on time?
b) A marketer from UPS jumps on the research stating, “They claim 95% on time, but by their own research they only ship 91% on time!” Provide a rebuttal to the UPS marketer in non-statistical terms.

Question

DHL Shipping claims that it ships 95% of its orders within three working days. You select a simple random sample of 100 orders and discover that only 91 of them shipped on time.

a) If DHL really does ship 95% on time, what is the probability that the company shipped 91 or fewer out of 100 orders were shipped on time?
b) A marketer from UPS jumps on the research stating, “They claim 95% on time, but by their own research they only ship 91% on time!” Provide a rebuttal to the UPS marketer in non-statistical terms.

anonymous · Answer

I know part a, I just need help with part b