Answer Happy

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, σ1​=σ2​=3 cm/s. From a random sample of size n1​=20 and n2​=20, we obtain xˉ1​=18.02 cm/s and xˉ2​=24.36 cm/s.
(b) What is the P-value of the test in part (a)? Round your answer to 3 decimal places (e.g. 98.765). P= (c) What is the β-error of the test in part (a) if the true difference in mean burning rate is 2.5 cm/s ? Round your answer to 5 decimal places (e.g. 98.76543).
Incorrect. Try again. Recall that a 100(1−α)% confidence interval for μ1​−μ2​ is given by xˉ1​−xˉ2​−zα/2​n1​σ12​​+n2​σ22​​​≤μ1​−μ2​≤xˉ1​−xˉ2​+zα/2​n1​σ12​​+n2​σ22​​​ where xˉ1​ and xˉ2​ are the means of independent samples of sizes n1​ and n2​ from populations with known variances σ12​ and σ22​. (d) Construct a 95\% confidence interval on the difference in means μ1​−μ2​. Round your answers to 3 decimal places (e.g. 98.765).