Comparing heights of older and younger people. People aged 50-60 were selected and measured, as were people aged 20-30. The statistics for the older crowd were: average: 66.7”, std dev: 5.1”. The...

  Comparing heights of older and younger people.   People aged 50-60 were selected and measured, as were people aged 20-30.  The statistics for the older crowd were: average: 66.7”, std dev: 5.1”.  The statistics for the younger crowd were: average: 67.4”, std dev 5.5”.  There were 250 people in each of the samples.
a)    What is the resulting 90% confidence interval for µold- µyoung?
b)    Are we getting taller?  Perform the test at the 1% level of significance.  Give all relevant output and state your conclusion.