Q1) Burning rates of 2 various solid-fuel propellants utilized in aircrew escape systems are being studied. It is known that both propellants have about same standard deviation of burning rate, that is σ1=σ2=3 centimetres per second. 2 random samples of n1=20 and n2=20 specimens are tested, sample mean burning rates are σ1=18 centimeters per second and σ2=24 centimeters per second.
a) Compute β-error of test in part (a) if true difference in mean burning rate is 2.5 centimeters per second.
b) Suppose equal sample sizes, what sample size is required to get power of 0.9 at a true difference in means of 14cm/s?