# Ashford bus 308 week 4 quiz with 100% correct answers

1. Question : The manager of the quality department for a tire manufacturing company wants to study the average tensile strength of rubber used in making a certain brand of radial tire. The population is normally distributed and the population standard deviation is known. She uses a Z test to test the null hypothesis that the mean tensile strength is less than or equal to 800 pounds per square inch. The calculated Z test Statistic is a positive value that leads to a p-value of .067 for the test. If the significance level is .10, the null hypothesis would be rejected.

False

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2. Question : For the chi-square goodness of fit test, the rejection point X2a is in

Student Answer:   the left tail of a chi-square curve.

both the left and right tails of a chi-square curve.

the right tail of the appropriate F curve.

the right tail of a chi-square curve.

3. Question : Consider using p-value to test H0 versus Ha by setting α equal to .10. We reject H0 at level α of significance if and only if the p-value is:

Student Answer:   Greater than α/2

Greater than α

Less than α

None of the above

4. Question : Type II error is defined as the probability of ______ H0 , when it should _____

Student Answer:    failing to reject, be rejected.

failing to reject, not be rejected.

rejecting, not be rejected.

rejecting, be rejected.

5. Question : The X2 statistic is used to test whether the assumption of normality is reasonable for a given population distribution. The sample consists of 5000 observations and is divided into 6 categories (intervals). The degrees of freedom for the chi-square statistic is:

6

5

4

3

6. Question : For a hypothesis test about a population mean or proportion, if the level of significance is less than the p-value, the null hypothesis is rejected.

False

7. Question : When carrying out a sample test (with ó known) of H0: µ = 10 vs. Ha: µ > 10 by using a rejection point, we reject Ho at level of significance a if and only if the calculated test statistic is

Student Answer:   less than Za

less than – Za

greater than Za/2

greater than Za

less than the p value.

8. Question : The X2 statistic from a contingency table with 6 rows and five columns will have _____ degrees of freedom.

24

5

20

25

9. Question : Homogeneity is a test of the null hypothesis that all multinomial probabilities are equal