The average (arithmetic mean) of a normal distribution of a school's test scores is 65, and standard...
The average (arithmetic mean) of a normal distribution of a school's test scores is 65, and standard deviation of the distribution is 6.5. A student scoring a 72 on the exam is in what percentile of the school?
Choices
Answer/Solution
68th percentile
Steps/Work
(78-65)/6.5 = 2 sigmas or 95.5th percentile for +-2 sigma but in our case we need only upper tail, so it's 100 - (100 - 95.5)/2 = 68th percentile
B
B