The burning rates of two different solid-fuel propellants used in aircrew escape systems are being studied. it is known that both propellants have approximately the same standard deviation of burning rate, that is sigma 1 = sigma 2 = 3 centimeters per second. two random samples of n 1 = 20 and n 2 = 20 specimens are tested, the sample mean burning rates are x 1 = 18centimeters per second and x 2 = 24 centimeters per second.
a) test hypothesis that both propellants have the same mean burning rate. use alpha = 0.05. what is the p - value ? .
b) construct a 95% confidence interval on the difference in means mu 1 - mu 2. what is the practical meaning of this interval?
c) what is the beta-error of the test in part (a) if the true difference in mean burning rate is 2.5 centimeters per second?