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

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

_____________________________

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

_____________________________

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

I.Answer the following problem. Show your complete solution.

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.

Step 2: The level of significance and critical value.

Level Significance = _____________________

z critical = _______________________

Type of test:______________________________

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

z computed=_______________________________

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 for food. Suppose you recently took a random sample of 25 households. You determined how much each household spent for 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 for 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= ____________________

t critical= _______________________

Type of test:______________________________

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

t computed =_______________________________

Step 4: Decision rule.

Step 5: Conclusion.