Cell phones and cell phone plans can be very expensive, so consumers must think carefully when choosing a cell phone and service.
The data service of a cell company is therefore an important factor in this decision
A student named Melanie from Los Angeles applies what she learned in her statistics class to help her make a decision about buying a data plan for her smartphone.
Melanie read an advertisement from the Cell Phone Giants (CPG, for short)
The CPG ad states that customers in Los Angeles get average data download speeds of 4 Mbps.
With this speed, the ad claims, it takes, on average, only 12 seconds to download a typical 3-minute song from iTunes.
Melanie has her doubts about this claim, so she gathers data to test it.
Melanie collects a random sample of size 45 downloads and found that it has an average download time of 13.5 seconds and the standard deviation as 3.2 seconds.
What can Melanie conclude? Her sample has a mean download time that is greater than 12 seconds. Isn't this evidence that the CPG claim is wrong?