Scores on a standardized test are normally distributed with a mean of 550 and a standard deviation of 45. approximately what percent of students scored between 560 and 580?

Given: Mean = 550, standard deviation = 45, scores 560 and 580.

Formula: 

Result: 

Go to a z score table and get probabilities associated with these z scores.



Note: More exact answers can be obtained via a stats calculator or Excel.

Final 0.7486 - 0.5871 = 0.1615 or 16.15%

Jeff

60 ÷ -20 x makes x = -3