I.Using the z table, find the critical value (or values) for each.

1. = 0.05, two-tailed test

___________

2. = 0.01, left-tailed test

___________

3. = 0.005, right-tailed test

___________

4. = 0.01, right-tailed test

___________

5. = 0.05, left-tailed test

___________

6. = 0.02, left-tailed test

___________

7. = 0.05, right-tailed test

___________

8. = 0.01, two-tailed test

___________

9. = 0.04, left-tailed test

___________

10. = 0.02, right-tailed test

II.For each conjecture, state the null and alternative hypotheses.

1.The average age of community college students is 24.6 years.

_____________________________

2.The average income of accountants is 51,497.00

_____________________________

3.The average age of attorneys is greater than 25.4 years.

_____________________________

4.The average score of high school basketball games is less than 88.

_____________________________

5.The average pulse rate of male marathon runners is less than 70 beats per minute.

_____________________________

6.The average cost of a DVD player is 399.50

_____________________________

7.The average weight loss for a sample of people who exercise 30 minutes per day for 6 weeks is 8.2 pounds.

_____________________________

8.The school Principal surveyed 150 teachers to findout if the salary significantly increased over the past 10 years.

_____________________________

9.A school owner wants to find out if male students perform better in Mathematics compared to female.

_____________________________

10.An economist wants to find out if there is a difference in the monthly expenses of families from Makati and Quezon City.

III.Answer the following problem. Show your complete solution in the space provided.

1.According to a study done last year, the average monthly expenses for mobile phone loads of high school students in Manila was Php350.00. A statistics student believes that this amount has increased since January of this year. Is there a reason to believe that this amount has really increased if a random sample of 60 students has an average monthly expense for mobile phone loads of Php380.00? Use a 0.05 level of significance. Assume that the population standard deviation is Php77.00.

Solution:

Step 1: State the hypothesis.

Ho:_____________________________________

Ha:_____________________________________

Step 2: The level of significance and critical value.

Level Significance = _____________________

= _______________________

Type of test:______________________________

Step 3: Compute for the value of one sample z test.

=_______________________________

Step 4: Decision rule.

Step 5: Conclusion.

2.According to last year's report, a Filipino household spends an average of Php400.00 per day on food. Suppose you recently took a random sample of 25 households. You determined how much each household spent on food each day and the results revealed a mean of Php390.00 and a standard deviation of Php21.50. Using a 0.01 level of significance, can it be concluded that the average amount spent per day on food has decreased? Assume normality over the population.

Solution:

Step 1: State the hypothesis.

Ho:_____________________________________

Ha:_____________________________________

Step 2: The level of significance and critical value.

Level Significance = _____________________

df= ____________________

= _______________________

Type of test:______________________________

Step 3: Compute for the value of one sample z test.

=_______________________________

Step 4: Decision rule.

Step 5: Conclusion.