A cell phone manufacturing company claims that their phone batteries last up to 48 hours without a single charge. A random sample of 5000 cell phone batteries was tested. The researcher classified...

Extracted text: A cell phone manufacturing company claims that their phone batteries last up to 48 hours without a single charge. A random sample of 5000 cell phone batteries was tested. The researcher classified each battery as either "stopped working (run out) before 48 hours", or "still working after 48 hours". A total of 55 out of the 5000 batteries stopped working in less than 48 hours. Which one of the following statements is incorrect? a) The variable of interest is all batteries that stop working (run out) b) The proportion 0.011 (55 out of 5000) is a sample statistic c) The population of interest is all batteries produced by this company d) The sampling unit is a battery