1. A group of 500 students have an average age of 18.4 years with a standard dev
ID: 3013385 • Letter: 1
Question
1. A group of 500 students have an average age of 18.4 years with a standard deviation of 0.9. The ages are normally distributed. Find the probability that a person is selected at random and is... a) at least 18 years old. b) at most 19 years old. c) between 17 and 19 years old, including 17 and 19. 2. using the information from problem 1, determine how old a person would be if they were in the 93'd percentile. Round their age to the nearest tenth of a year. 3. Using the information from problem 1again, what ages would make up the middle 50% of the sample? 4. The student average from the AFM statistics test is 81% with a 1.1 standard deviation. What would a person need to score if he or she wanted to be 1.25 standard deviations below the mean? 5. Person A ran a race in 110 seconds. The average time for this race was 113 seconds, with a standard deviation of3 seconds. Person B competed in a long jump event and jumped 84 inches. The average jump was 80 inches with a standard deviation of 4. With this information, determine who did better amongst their peers.Explanation / Answer
5.
A ran 110
Avrage of this race = 113, with stdev = 3
Z = 110-113 / 3 = -1
B jumperd 84, averae jump was 80, stdev=4
Z = 84-80 / 4= +1
Since, over the same scale of normalized Z, we have the fact that +1 of B is more than -1 for A.
So , B has overformed in his/her event compared to A in his/her own event
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.