Step-by-step explanation:
STEP 1 : FIND THE MEAN
STEP 2 : SUBRACT THE MEAN FROM EACH SCORE
STEP 3 : SQUQRE EACH DEVIATION
STEP 4 : ADD THE SQUARE DEVIATION
STEP 5 : DIVIDE THE SUM BY THE NUMBER OF SCORES
STEP 6 : TAKE THE SQUARE ROOT OF THE RESULT FROM STEP 5
HOPE IT HELPS