For a normal curve with mean 5 and standard deviation 7, which of the following parts of the normal curve will have an area of approximately 68%?
A)from 1.5 to 8.5
B)from -2 to 12
C)from 5 to 19
D)from -9 to 19

Question

Quizplus · Accepted Answer

The range from -2 to 12 includes one standard deviation on either side of the mean (5-7=-2, 5+7=12), which is known to contain approximately 68% of the area under the curve according to the empirical rule. Therefore, answer choice B is the best option. The 68% falls within one standard deviation of the mean, so we need to find the range that covers one standard deviation on either side of the mean. 
One standard deviation below the mean is (5-7)= -2 and one standard deviation above the mean is (5+7)= 12. 
Therefore, the range from -2 to 12 will have an area of approximately 68%.

For a Normal Curve with Mean 5 and Standard Deviation