Statistic
P1-2010-2011-Spring Bus531
Standard Normaal Probability Problems
1- A university reported admission statistics for 3339 students who were admitted for freshmen for the fall semester of 1998. Of these students, 1590 had taken the Scholastic Aptitude Test (SAT). Assume the SAT verbal scores were normally distributed with a mean of 530 and a standard deviation of 70. a – What percentage of students were admitted with SAT verbal scores between 500 and 600? b - What percentage of students were admitted with SAT verbal scores of 600 or more? c - What percentage of students were admitted with SAT verbal scores of 480 or less? d - What percentage of students were admitted with SAT verbal scores between 565 and 635? e - What percentage of students were admitted with SAT verbal scores between 450 and 500? f – Above which SAT score top 10 % of the students fall? g – Below which SAT score bottom 20 % of the students fall?
2-The average time it takes a four person - crew to build the frame of a certain type of house is two 40-weeks, or (4 workers) (2 weeks) (40 hoýrs per week) = 320 labor hours. The standard deviation is 50 labor - hours. If framing time is normally distributed, what is the probability that the time to frame a house is a) more than 320 labor - hours? b) from 280 to 360 labor hours? c) more than 260 labor hours? d)from 260 to 300 labor hours? e) less than 250 labor hours? f) from 300 to 350 labor hours?
3 - (Refer problem 2) If the company promises to frame a house within an agreed upon number of labor hours and wishes to have at most 90 percent chance of fulfilling the promise, what should be the agreed upon number of labor hours?
4-A new machine used for filling cans of liquid hairspray can be set for any average fill. If the amount of fill is normally distributed around a setting with a standard deviation of 1.5 gr, a-(10 pts.) If the average fill is 370 gr what is the proportion of the cans that contain between 367 and 369?
Standard Normaal Probability Problems
1- A university reported admission statistics for 3339 students who were admitted for freshmen for the fall semester of 1998. Of these students, 1590 had taken the Scholastic Aptitude Test (SAT). Assume the SAT verbal scores were normally distributed with a mean of 530 and a standard deviation of 70. a – What percentage of students were admitted with SAT verbal scores between 500 and 600? b - What percentage of students were admitted with SAT verbal scores of 600 or more? c - What percentage of students were admitted with SAT verbal scores of 480 or less? d - What percentage of students were admitted with SAT verbal scores between 565 and 635? e - What percentage of students were admitted with SAT verbal scores between 450 and 500? f – Above which SAT score top 10 % of the students fall? g – Below which SAT score bottom 20 % of the students fall?
2-The average time it takes a four person - crew to build the frame of a certain type of house is two 40-weeks, or (4 workers) (2 weeks) (40 hoýrs per week) = 320 labor hours. The standard deviation is 50 labor - hours. If framing time is normally distributed, what is the probability that the time to frame a house is a) more than 320 labor - hours? b) from 280 to 360 labor hours? c) more than 260 labor hours? d)from 260 to 300 labor hours? e) less than 250 labor hours? f) from 300 to 350 labor hours?
3 - (Refer problem 2) If the company promises to frame a house within an agreed upon number of labor hours and wishes to have at most 90 percent chance of fulfilling the promise, what should be the agreed upon number of labor hours?
4-A new machine used for filling cans of liquid hairspray can be set for any average fill. If the amount of fill is normally distributed around a setting with a standard deviation of 1.5 gr, a-(10 pts.) If the average fill is 370 gr what is the proportion of the cans that contain between 367 and 369?