I. Directions: Read the questions carefully and write the letter of the correct answer in a sheet of paper.

1. It is the most important probability distribution of a continuous random variable that shows the graphical representations of a

random variables obtained through measurements.

a. Poisson Distribution b. Normal Distribution c. Geometric Distribution d. Bernoulli Distribution

2. The bell- shaped graph that lies entirely above the horizontal axis is called _________.

a. pie graph b. Histogram c. Normal curve d. Modal curve

3. Which of the following terms measures how many standard deviation a given value (x) is above or below the mean?

a. standard score b. mean score c. y- score d. x- score

4. Which of the following is NOT TRUE about normal curve?

a. The peak of the normal curve is at the center.

b. The normal curve is symmetrical to the center.

c. The normal curve is modal and asymptotic to the horizontal axis.

d. The mean, median and mode coincide at the center.

5. It determines the location of the center of the bell - shaped curved.

a. standard deviation b. mean c. variance d. mode

6. The larger value of standard deviation yields a skinnier and taller normal curve.

a. true b. false c. sometimes true d. sometimes false

7. What is the area under the curve falls within 2 standard deviation to the mean?

a. 68% b. 80% c. 95% d. 99.7%

8. What z-score value that corresponds to a normal random variable x=93 in the given mean of 85 and standard deviation 8 of

population in Statistics test?

a. 0 b. 1 c. 2 d.3

For number 9 - 11, refers to the situation below

In a Science test, the mean score is 42 and the standard deviation is 5. Assuming the scores are normally

distributed, what percent of the score is

9. greater than 48?

a. 10. 51% b. 11.51% c. 12.51% d. 13.51%

10. less than 50?

a. 81.50% b. 85.65% c. 90.51% d. 94.52%

11. between 30 and 48?

a. 70. 55% b. 83.57% c. 87.67% d. 90.24%

For number 12-13, refers to the situation below

The length of human pregnancies from conception to birth approximates a normal distribution with a mean of 266 days

and a standard deviation of 16 days.

12. What proportion of all pregnancies will last between 240 and 270 days?

a. 0.2345 b. 0.4452 c. 0.5471 d. 0.6578

13. What length of time marks the shortest 70 % of all pregnancies?

a. 274.32 b. 292.42 c. 187.67 d. 190.24

14. What is the area between and ?

a. 0.0279 b. 0.3023 c. 0.0606 d. 0.4633

15. What is the area to the right of ?

a. 0.4641 b. 0.9641 c. 0.4357 d. 0.9941

16. What is the are between and ?

a. 0.4505 b. 0.9958 c. 0.3962 d. 0.5000

17. The mean height of grade 9 students at a certain school is 164 cm and the standard deviation is 10 cm. Assuming the heights

are normally distributed. What percent of the heights is greater than 168 cm?

a. 24.50% b. 28.54% c.30.15% d. 34.46%

For number 18-20, refers to the situation below

The systolic blood pressure for a certain group of people follows a normal distribution with and. Find the probability that a

randomly selected person from the group will have a systolic blood pressure

18. above 135.

a. 0. 55% b. 0.57% c. 0.13% d. 0.24%

19. below 110

a. 2. 55% b. 2.57% c. 2.17% d. 2.28%

20. between 115 and 140

a. 99.38% b. 93.58% c. 87.67% d. 80.24%