Chapter 3.3, Problem 6BSC

z Scores. In Exercises 5-8, express all z scores with two decimal places.

5. ATL Data Speeds For the Verizon airport data speeds (Mbps) listed in Data Set 32 “Airport Data Speeds” in Appendix B, the highest speed of 77.8 Mbps was measured at Atlanta’s (ATL) international airport. The complete list of 50 Verizon data speeds has a mean of $\bar{x}=17.60$ Mbps and a standard deviation of s = 16.02 Mbps.

a. What is the difference between Verizon’s data speed at Atlanta’s international airport and the mean of all of Verizon’s data speeds?

b. How many standard deviations is that [the difference found in part (a)]?

c. Convert Verizon’s data speed at Atlanta’s international airport to a z score.

d. If we consider data speeds that convert to z scores between −2 and 2 to be neither significantly low nor significantly high, is Verizon’s speed at Atlanta significant?

6. PHL Data Speeds Repeat the preceding exercise using the Verizon data speed of 0.8 Mbps at Philadelphia International Airport (PHL).