Question

1 pts Question 9 The burning rates of two different solid-fuel propellants used in air crew escape systems are being studied. It is known that both propellants have approximately the same standard deviation of burning rate, with a value of 3 cm/s. Two random samples of size 20 each are tested; the sample means are recorded as 18 and 24 cm/s. What type of hypothesis tests would be most appropriate if we wanted to test the hypothesis that both propellants have the same burning rate? O2 Sample Z-Test O2 Sample T-Test Chi Square Test O2 Sample F-Test Question 10 1 pts An article in Fire Technology investigated two different foam-expanding agents that can be used in the nozzles of fire fighting equipment. A random sample of five observation with an aqueous film forming foam had a sample mean of 4.7 and a standard deviation of 0.6. A random sample of five observations with alcohol-type concentrates had a sample mean of 6.9 and a standard deviation of 0.8 What type of hypothesis test would be most appropriate to determine if there is a difference in the mean foam expansion? O 2 Sample T-Test 2 Sample Z Interval 2 Sample F-Test O 2 Sample Z-Test

Answer 1

Question 9

As the population standard deviations are known,

The type of the test that would be most appropriate if we wanted to test the hypothesis that both propellants have the same burning rate

Ans:

2 sample Z-test

Question 10

As the population standard deviations are not known, and the sample standard deviations are known ;

The type of hypothesis test that would most appropriate to determine if there is a difference in the mean foam expansion

2 sample T-Test