For this problem I found the mean however I cannot seem to find the standard deviation. I tried everything for the formula to adding, subtracting, multiplying, dividing but still no correct answer. Can someone please help and explain how you got the answer?

What values of data might affect the statistical measures of spread and center

Find the value of x for which line a is parallel to line b

What is the probability of throwing several dice with sum equal to 6 (six)? show the ways of possibilities for sum 6 (as the numerator) and the ways of throwing n dices for n = 1, 2, 3, 4 or 5 as denominator for all the questions to earn full credits. (a)throw one die, (b) throw two dice, (c) throw three dice (d) throw 4 dice, (e) throw 5 dice