Math Answers

 A report in LTO stated that the average age of taxis in the Philippines is 12 years. An operations manager of a large taxi company selects a sample of 40 taxis and finds the average age of the taxis is 11.2 years. The standard deviation of the population is 2.3 years. At 0.05 level of significance, can it be concluded that the average age of the taxis in his company is less than the national average?

Average Senior High School annual cost of tuition fee for all private schools last year was P46,300. A random sample of costs this year for 45 private schools indicated that the sample mean was P47,800 and a sample standard deviation was P5,600. At the 0.10 level of significance, is there sufficient evidence to conclude that the cost has increased?

If the domain of f

f is -3\le x \le 3

−3≤x≤3, what is the range

A TV manufacturer claims that the life span of its regular TV sets is 12 years with a standard

deviation of 1.2 years. Using a random sample of their 20 TV sets, the average life span is found

to be 11.2 years. Test the hypothesis that the T sets’ life span of 12 years as claimed by the

manufacturer is true at 0.05 level.

For items 9 to 10, refer to the given table below.

Mathematics Quiz Scores of 15 Grade-10 Aphrodite Student

Name Score

Amy 17

Michelle 17

Aila 17

Evan 11

Albert 11

D-anne 16

Sarah 15

Isaac 18

Aidan 19

Carl 12

Cherry 17

Jethro 14

Angelo 16

Nica 18

Noah 15

9. If 1 is 12, how many students belong to the lowest 25%?

10. If 5 is 16, how many students belong to the lower 50%?

Lilian got a score of 55, which is equivalent to the 70th percentile in a mathematics test. Which of the following is NOT true?

A. 70% of the students got a score less than or equal to Lilian’s score.

B. Thirty percent of the class got scores of 55 and above.

C. If the passing mark is the first quartile, she passed the test.

D. Her score is below the 5th decile.

Which is a correct statement about the function f (x) = 5x from the set

of integers Z to the set of integers?

3. The set of scores: 15, 14, 12, 10, 9, 11, 17, 15, and 19, find the median score.

M. 9 T. 11 A. 10 H. 14

2. What do you call the ninety-nine score points which divide a distribution into one hundred equal parts? M. decile T. percentile A. median H. quartile

The purchasing director of an industrial part factory is investigating the possibility of purchasing a new type of milling machine. He determines that the new machine will be bought if there is evidence that the parts produced have a higher mean breaking strength than those from the old machine. The population standard deviation of the breaking strength for the old machine is 10kg and for the new machine is 9 kg. A sample of 100 parts was taken from each machine. Old machine indicates a sample mean of 65kg while new machine indicates a sample mean of 72 kg. Using the 0.01 level of significance, is there evidence that the purchasing director should buy the new machine? (critical value = + 2.575 )