4. Let X be a normally distributed random variable with mean 120 and standard deviation 8. If x=100, what is the corresponding z-score? A. -2.5 B. 0.25 C. -0.25 D. 2.5 5. What percent of the area under the normal curve is less than z = -1.78? A. 96.25% B. 46.25% C. 13.75% D. 3.75% For number 6-10, find the area under the normal curve of the following cases. 6. To the left of z = 2.86 A. 0.0021 B. 0.4979 7. Between z = 1.15 and z = 2.89 A. 0.1232 B. 0.3749 8. Between z = 0 and z = 1.75 A. 0.9959 9. To the left of z = -1.24 A. 0.1075 B. 0.8459 B. 0.3925 10. Between z = -1.46 and z= 2.15 A. 0.0563 B. 0.4279 C. 0.5021 C. 0.4981 C. 0.4599 C. 0.6075 2 C. 21.90% 12. What is the z-score that corresponds to 180 grams? A. -1.60 B. -1.70 C. 1.60 13. What is the z-score that corresponds to 250 grams? A. -1.20 B. -3.20 C. 1.20 D. 0.9979 C. 0.4842 D. 0.9121 11. The division - wide aptitude test in Mathematics was conducted to students. The mean of the test is 58 and the standard deviation is 12. The scores also approximate the normal distribution. What percent of the scores is between 55 and 65? A. 18.23% B. 31.77% For numbers 12-14, refer to the problem below. It is known that the weights of mangoes harvested in a farm are normally distributed with a mean of 220 grams and a standard deviation of 25 grams. D. 0.8730 D. 0.0401 D. 0.8925 D. 9.87% D. 1.70 D. 3.20 14. If a mango is selected at random, what is the probability that its weight lies between 180 and 250 grams? A. 0. 8849 B. 0. 8301 C.0.4452 D. 0. 3849 15. The average monthly salary for a newly hired employee at a bank is P20,000. If the hiring salary at this bank is normally distributed with a standard deviation of P2,800, what is the probability that a newly hired employee randomly selected from a list of receives a monthly salary which is less than P16,000? A. 0.9236 C. 0.0764 B. 0.8489 D. 0.1151​