1. ToysRUs wants to construct a confidence intervalfor the life of its toys. Whi

Question

1.   ToysRUs wants to construct a confidence intervalfor the life of its toys. Which of the following confidenceintervals will be narrower and why: one based on aZ-distribution or one based on at-distribution?         

2.   A confidence interval of 90% was used to estimatethe proportion of customers who buy at least two items during theirshopping mall experience. A random sample of 150 customersproduced the following confidence interval: 30% +/- 5%. Whatis the best way to explain the results?

4.   True or false?

b) An error is committed when the null hypothesis isrejected when it is false.

c) When you are conducting the t test, the population must beapproximately normally distributed.

Explanation / Answer

1. Z-distribution (we pretend we know , so we have moreinformation and thus more certainty about what the mean actuallyis) 2. We are 90% confident that between 25% and 35% of customers willbuy at least two items. 9 out of 10 such random samples will yielda confidence interval that contains the true proportion ofcustomers who will buy two more more items. 4. a) T     b) F     c) T

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.