In a study of smoking and its effects on sleep patterns, onevariable is the time that it takes to fall asleep. A random sampleof size 12 is drawn from the population of smokers; an independentsample of size 15 is drawn from the population of non-smokers. Themean time to sleep for smokers is 43.70 minutes; for non-smokers itis 30.32 minutes. The sample variance for the time to sleep forsmokers is 286.549 min2  while for non-smokers it is50.806 min2 .
Find a 95% confidence interval to determine if these dataindicate that smokers tend to take longer to fall asleep thannon-smokers. (Hint: Degrees of freedom formula yields df =14.2)
