A catalog sales company promises to deliver orders placed on the Internet within 3 days. Follow-up calls to a few randomly selected customers show tha

alesterp 2020-12-16 Answered
A catalog sales company promises to deliver orders placed on the Internet within 3 days. Follow-up calls to a few randomly selected customers show that a 95% confidence interval for the proportion of all orders that arrive on time is 88
a) What does this mean? Are these conclusions correct? Explain.
b) 95% of all random samples of customers will show that 88% of orders arrive on time.
c) 95% of all random samples of customers will show that 82% to 94% of orders arrive on time.
d) We are 95% sure that between 82% and 94% of the orders placed by the sampled customers arrived on time.
e) On 95% of the days, between 82% and 94% of the orders will arrive on time.
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Brighton
Answered 2020-12-17 Author has 103 answers
a) Incorrect. This implies certainty.
b) Incorrect. Different samples will give different results. Many fewer than 95% will have 88% on-time orders.
c) Incorrect. The interval is about the population proportion, not the sample proportion in different samples.
d) Incorrect. In this sample, we know 88% arrived on time
e) Incorrect. The interval is about the parameter, not about the days.
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