Question

FILE TOOLS VIEW Documents - Word (Product Activation Failed) 0 - 0 a. In UTP, a recent study from 150 maintenance iv. Find the number of workers that the workers showed that the mean daily wages was RM 30 with the standard deviation of RM salary is less than RM 25 per day 6. Assume the distribution follows normally. Find the probability that the workers earn: [2 marks] i. Between RM 40 and RM 45 per day [3 marks] End of document I ii. More than RM 20 per day [3 marks] Less than RM 25 per day [3 marks]

Answer 1

the pdf of normal distribution is = 1/0* V2n * e^-(x-u)^2/ 2012 standard normal distribution is a normal distribution with a, mean of 0,standard deviation of 1 equation of the normal curve is ( z )= x-u / sd ~ n(0,1) mean (u) = 30; standard deviation ( sd )= 6 a. to find pla <= z< = b) = f(b) - f(a) p(x < 40) = (40-30)/6 = 10/6 = 1.6667 = p (z <1.6667) from standard normal table = 0.9522 p(x < 45) = (45-30)/6 = 15/6 = 2.5 = p ( z <2.5) from standard normal table = 0.9938 p(40 < x < 45) = 0.9938-0.9522 = 0.0416 b. p(x > 20) = (20-30)/6 = -10/6 = -1.6667 = p (z >-1.6667) from standard normal table = 0.9522 c. p(x < 25) = (25-30)/6 = -5/6= -0.8333 = p (z <-0.8333) from standard normal table = 0.2023 d. number of workers that the salary is less than rm 25 per day = 0.2023 * 30 = 6.069 ~ 7 workers has less than rm 25