= 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 ₂ = 3 centimeters per second. Two random samples of n₁ = 20 and n₂ = 20 specimens are tested; the sample mean burning rates are 18 centimeters per second and ₂ = 24 centimeters per second. (a) (b) (c) = Test hypothesis that both propellants have the same mean burning rate. Use a 0.05. What is the P-value ?. Construct a 95% confidence interval on the difference in means 4-2. What is the practical meaning of this interval? What is the 6-error of the test in part (a) if the true difference in mean burning rate is 2.5 centimeters per second?