USA Today reported that the state with the longest
mean life span is Hawaii, where the population mean life span is 77 years.
A random sample of 20 obituary notices in the Honolulu Advertizer gave the
following information about life span (in years) of Honolulu residents:
72 68 81 93 56 19 78 94 83 84
77 69 85 97 75 71 86 47 66 27
i. Use a calculator with mean and standard deviation keys to verify that
x 5 71.4 years and s < 20.65 years.
ii. Assuming that life span in Honolulu is approximately normally distributed, does this information indicate that the population mean life span for
Honolulu residents is less than 77 years? Use a 5% level of signifi cance.


Answer :