Confidence Interval for a Population Mean.
A study of the ages o the motor cyclists killed in crashes involves the random selection of 150 drivers with a mean of 37.1 years. assume that σ=12.0, construct a 99 percent confidence interval estimate of the mean age of all motor cyclists killed in crashes. If the confidence interval limits do not comprise age below 20 does it mean that motor cyclists under the age of 20 rarely die in crashes?