+ |CD Page view (E) 0.5385 Questions 26 and 27 are based on the following information: Suppose the ages (in years) of the Tuks athletes who competed in the 2013 Comrades Marathon has a normal distribution with mean / =40 and standard deviation o = 6. Question 26 (2) What percentage of ages lies within three standard deviations of the mean? (A) 68.26% (B) 95.44% (C) 99.74% (D) 99.87% (E) 100% Question 27 (2) What is the probability that a randomly selected athlete is older than 45 years? ) 0.8333 (B) 0.7967 (C) 0.4443 (D) 0.2033 (E 0.0207 STK110 EXAM / EKSAMEN 2013-06-10 23 Questions 28 to 35 are based on the following information: Let p denote the population proportion of Tuks athletes who successfully finished the 2013 Comrades Marathon. Ho : p 0.75. The results of a random sample of 20 athletes are as follows: search OBb 21548139 x _ common esca x 8 www.bing.com x pd Escape Sequer X File | C:/Users/27823/Downloads/stk110_2013_exam.pdf + |CD Page view IA (A) 0.1153 (B) 0.1480 (C) 0.1764 (D) 0.2094 (E) 0.2318 Questions 36 to 43 are based on the following information: Nosnow Cannotski is a sprinter from the Tuks athletics club. Let x be the time duration (in minutes) for a randomly selected training session of Nosnow. Suppose x has a uniform probability distribution over the interval 40 to 100 minutes with variance oz =300. Let x be the average time duration of 75 training sessions. Question 36 (1) The density function for x is: (A) f ( x) = for 40 Sux $ 100 (B) f(x) = 60 for 40 S x $ 100 0 elsewhere 0 elsewhere (C) f( x)= 70 for 40 x $ 100 (D) f (x) = for 40 S x $ 100 0 elsewhere 0 elsewhere (E) f (X) = 100 for 40 x $ 100 0 elsewhere Question 37 (1) The expected time duration for a randomly selected training session is: (A) 40 minutes (B) 60 minutes (C) 70 minutes (D) 75 minutes (E) 100 minutes STK110 EXAM / EKSAMEN 2013-06-10Bb 21548139 x common esca > www.bing.com x pd Escape Sequer X File | C:/Users/27823/Downloads/stk110_2013_exam.pdf + CD Page view Question 38 (1) The probability that the time duration for a randomly selected training session will be exactly 50 minutes is: (A) 40 (B) 50 C) (D (E) 0 Question 39 (2) P(80