Question

suppose 160 geology students measure the mass of an ore sample. due to the human error and limitations in the reliability of the balance not all the readings are equal the result are found to closely approximate a normal curve with the mean 85 g and the standard deviation 1 g . use the symmetry of the normal curve and the empirical rule

Answer 1

In a group of samples find the deviation

there are 160 students

mean is the sum of samples/ number of samples

standard deviation is a number defined by

Deviation = √ sum of squares = 1

Then find number of students with readings more than 85g

looking at the curve. 80 students are measuring more than 85g, and substracting deviation standard= 1 . The result more precise is 80-1= 79 students