Face masks used by firefighters often fail by having their lenses fall out when exposed to very high temperatures. A manufacturer of face masks claims that for their masks the average temperature at which pop out occurs is 550°F. A sample of 75 masks are tested and the average temperature at which the lense popped out was 470°F. Based on this information is the manufacturer's claim valid?
a. Identify the population of interest to us in this problem.
b. Would an answer to the question posed involve estimation or testing a hypothesis?