9-1 t tests and the cost of Levi's jeans and H&M dresses in Halifax: Numbeo is a crowd-sourced Web site that gathers data on cities and countries around the world (numbeo.com/cost-of-living). The data are searchable by city or country. For example, when we looked up Halifax, Canada, we discovered that a pair of jeans ("Levis 501 or similar") goes for an average of $55.23 (Numbeo, 2017). The range was $40 to $70. And a summer dress from somewhere like Zara or H&M goes for an average of $42.37, with a range of $30 to $50. Numbeo also tells us that its Halifax data are based on contributions from 147 different people.

a.Let's say that Levi Strauss & Co. agreed to tell you the mean price (in Canadian dollars) of Levi's 501 jeans around the world. If you wanted to test whether Levi's 501 jeans in Halifax cost a different amount from the world price, is this a one-tailed or a two-tailed test?What hypothesis statements would you use?

i.One-tailed or two-tailed?

ii.Hypotheses in words

H₁:

H₀:

iii.Hypotheses in statistical notation:

H₁:

H₀:

b. What additional information would you need to conduct the hypothesis test that you identified in part (a)?

c.Thinking back to Chapter 5, what kind of sample is this? What concerns might you have about this kind of a sample?

d.Numbeo doesn't tell us how many of the 147 contributors answered each of these questions. Why might the sample be even smaller than 147 for the average cost of summer dresses?