In: Statistics and Probability
The burning rates of two different solid-fuel propellants used in rocket systems are being studied. It is known that both propellants have approximately the same standard deviation of burning rate, that is 3cm/second and assume be normally distributed. Two random samples with the same sample size of 20 specimens are tested and the sample mean burning rates are 18 cm/second and 24 cm/second respectively.
i. Test the hypothesis that one propellants have a higher average burning rate, using the P-value approach.
ii. Construct a two-sided 95% CI on the difference in means, m1 − m2 . What is the practical meaning of this interval?
Solution
We are 95% confident that the difference between burnng rates of two solid fuel propellants falls in the interval (-7.86, -4.14).