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 iscentimeters per second. Two random samples ofandspecimens are tested; the sample mean burning rates arecentimeters per second andcentimeters per second.

(a) Test the hypothesis that both propellants have the same mean burning rate. Use. What is the-value?

(b) Construct a 95% confidence interval on the difference in means.

(c) What is the-error of the test in part (a) if the true difference in mean burning rate is 2.5 centimeters per second?

(d) Assuming equal sample sizes, what sample size is needed to obtain power of 0.9 at a true difference in means of 4 cm/s?

(a) The null hypothesis

is not

is

rejected. The-value is

[Round your answer to 3 decimal places.](b) The 95% confidence interval is (

,

) Round your answer to two decimal places (e.g. 98.76).

(c)

Round your answer to five decimal places (e.g. 98.76543).

(d)

Round your answer to the next integer.