the graph shows the scores of an exam. the mean is 84 and the standard deviation is 2.5. about what percent of students scored within one standard deviation of the mean

Answer with explanation:
Mean of the Data set which is Normally Distributed =84
Standard Deviation =2.5
Data values which lie within one standard Deviation that is between , (84-2.5=81.5) to (84+2.5=86.5) is given by [tex]Z_{score}[/tex].
Which states that 68% of the data lie between one standard deviation ,that is between values 81.5 to 86.5 of all variate.