The heights of 600 students were measured. The mean was found to be 65 inches with a standard deviaton of 2.5 inches. If the heights are approximately normally distributed, then 95% of the students should be between which 2 heights?
________ and ________
How many of the students should be less than 5 feet tall?
Thank You very much..
2007-12-13 03:13:57 · 2 answers · asked by azen 1 in Science & Mathematics ➔ Mathematics
95% of the normally distributed data will be within 2 standard deviations of the mean, 65 ± 2(2.5) = 65 ± 5, which means between 60 and 70.
2007-12-13 03:17:45 · answer #1 · answered by Philo 7 · 0⤊ 0⤋
95% is +/- 2 standard deviations = +/- 5 inches
60 and 70 inches
That leaves 5% are either less than 60 or greater than 70 inches tall. Since it is evenly distributed, 2.5% would be less than 5 feet tall.
2007-12-13 11:27:42 · answer #2 · answered by T 5 · 0⤊ 0⤋