Question

The class mean score on a test was $60$, and the standard deviation was $15$. lf Elena's score was within $2$ standard deviations of the mean, what is the lowest score she could have received?

• A. $20$
• B. $30$
• C. $40$
• D. $50$

Answer 1

The correct option is B $30$

Elena's score was within $2$ standard deviations of the mean. Since one standard deviation is $15$, her score is no more than $15\times 2=30$ points from the mean. The lowest possible score she could have received, then, is $60-30$, which is equal to $30$.