Question

Theodore is the owner of FlightPro (an app that provides maps and real-time weather reports for pilots) and is not satisfied with the map download speeds on electronic devices (μ = 90 seconds, σ = 30 seconds, normally distributed). So, he hires a software developer to reprogram the map feature in FlightPro with the hope that map download speeds will have an extreme decrease in download speeds. After the software update, Theodore takes a sample of 9 electronic devices and finds a mean speed of 60 seconds for a map of the Las Vegas airspace to download. What is the difference in download speeds between the mean download speed in the sample versus the mean download speed in the original population Theodore should expect to observe just due to random chance (even if the update had no effect)?

Can you please show your work so I know how to answer the problem myself?

a. 10

b. 30

c. 6.67

d. 3.33

Answer 1