For the data set below which of the following is true

Question

For the data set below whitch one is true
9,8,6,7,8,5,6,9,7,7
a) the equallaterial range is greater than the range
b)the range is five
c)the standard deviation is approximately 2.5.

D) the range is 6

Answer 1

mean is 7.2

sum of squares: 15.6

number: 10

variance: 1.56

standard deviation about 1.25

range = 9-5 = 4

You can do this with tedious calculations

take each data point and subtract the mean

9-7.2 = 1.8 then square it to get 3.24

8-7.2 = 0.8 squared = 0.64

7-7.2 = 0.2 squared = 0.04

6-7.2 =-1.2 squared = 1.44

5.7.2 = -2.2 squared = 4.84

3.24 x 2

.064 x 2

.04 x 3

1.44 x 2

4.84 x 1

add them up to get 15.6 = sum of squares

if these 10 data points are the entire population

then divide by 10 to get 1.56 = variance

standard deviation is the square root of 1.56 = about 1.25

but if this is "just" a sample then divide by n-1 =10-1 =9

to get the variance = 15.6/9 = 1.7333...

square root = square root of 1.7333...= about 1.32

range is the largest minus the smallest = 9-5 = 4

or you can go on line and find a website with a standard deviation calculator that does the computations for you

just google standard deviation calculator and a couple websites pop up. then put in the 10 numbers, and it spits out all the above and more.