Find the standard deviation for the set of data. {15, 17, 13, 20,7,7, 21, 22,4}

A. 7.09
B. 6.31
C. 6.39
D. 6.8

Which of the following transformations will make coincide with ? a. counter-clockwise rotation 90º about a, followed by a translation 5 units to the right b. translation 5 units to the right, followed by a reflection across the y-axis c. translation 5 units to the right, followed by a reflection across the x-axis d. translation 1 unit up and 5 units to the right, followed by a reflection across the x-axis