1) The speeds of car traveling on Interstate Highway I-35 are normally distributed with a mean of 74 miles per hour and a standard deviation of 6 miles per hour.
(a) Find the standardized variable for the speeds of car traveling on I-35.
(b) Find the percentage of the cars traveling on this highway with a speed
i. of more than 85,
ii. between 65 to 72.
(c) If a BMW is at the speed that is faster than 90 percentage of cars, what is the speed of the BMW?
2) The raw scores in a national aptitude test are normally distributed with mean 506 and standard deviation 81.
(a) What proportion of the candidates scored below 574?
(b) If a student obtains a score such that 98% of the students' scores are lower than hers, what is her score?