The mean of a data set is equal to 10 and its standard deviation is equal to 1. If we add 5 to each data value, then the mean and standard deviation become	Select the correct option:
A) mean = 15 , standard deviation = 6 B) mean = 10 , standard deviation = 6 C) mean = 15 , standard deviation = 1 D) mean = 10 , standard deviation = 1 E) None
Solution   Since 5 is added to all data values, the mean will also increase by 5 and becomes 15. But the standard deviation which measure the "distance" between the mean and the data values does not change.   Answer mean = 15 , standard deviation = 1
<result>C</result>
The mean of a data set is equal to 10 and its standard deviation is equal to 1. If we add 5 to each data value, then the mean and standard deviation become