Data Set 25 35 34 56 70 What is the sample s standard deviat

Data Set: 25, 35, 34, 56, 70

What is the sample, s, standard deviation of the above data?

Data Set: 6, 3, 5, 6, 8, 8

What is the sample mean of the above data?

Solution

Q1.

Step 1:Add them up:
25+ 35+ 34+ 56+ 70 = 220

Step 2: Square your answer:
220 × 220 = 48400
…and divide by the number of items. We have 11 items in our example so:
48400 / 5= 9680
Set this number aside for a moment.

Step 3: Take your set of original numbers from Step 1+ and square them individually this time:
25^2+35^2+34^2+56^2+70^2= 11042

Step 4: Subtract the amount in Step 2 from the amount in Step 3.
11042 - 9680 = 1362
Set this number aside for a moment.

Step 5: Subtract 1 from the number of items in your data set. For our example:
5 – 1 = 4

Step 6: Divide the number in Step 4 by the number in Step 5. This gives you the variance:
1362/ 4 = 340.5
How to find the sample variance and standard deviation: Standard Deviation

Step 7: Take the square root of your answer from Step 6. This gives you the standard deviation:

340.5 = 18.45

Q2.

Mean = (6+3+5+6+8+8)/6 = 6