Question

Keith's long jump distances in feet from the last 3 track meets:23.8, 23.0 ,22.6 ,24.2 ,23.8 ,22.5 ,23.1 ,24.0.
What is the standard deviation? please help me work this out !

Answer 1

to find standard deviation you need to find two things before it. do you know what?

Answer 2

mean and range

Answer 3

mean=23.4
range=1.7
median=23.5

Answer 4

good, so whats the mean?

Answer 5

ok so the mean is 23.4, what do you do next?

Answer 6

Do you take the mean and square it by each of the distances

Answer 7

perfect! thats called variance....so (23.8-23.4)^2 + (23-23.4)^2 +.....

Answer 8

after you calculated that you divide your answer by the number of pieces of data, so in this case 8

Answer 9

oh ok let calculate of these and I will get back with you in a few min.

Answer 10

thats fine, im doing it too so we can compare answers

Answer 11

ok so heres what i got: Variance= (3.02)/(8)
variance = .3775
to find standard deviation, you take the square root of the variance
sqrt(.3775) = .614
so the standard deviation = .614

Answer 12

you're going to want to follow that same procedure for any other types of problems like that

Answer 13

ok thanks for you help