- find the standard deviation of 1, 5, 4, 2, 6, 2, 1,1 5,3
- find the standard deviation of 20, 17, 17, 14, 12, 11, 7, 8, 9, 16, 19, 22
A sample of data can have a lot of different numbers and it will require grouping to make any sense e.g 3-5 hrs, 6-8 hrs, 9-11 hrs, 12-14 hrs, 15-17 hrs, 18-20 hrs can represent the difefrnt ranges to group the numbers
Find the standard deviation for
0-4 2
5-9 7
10-14 12
15 - 19 17
20-24 22
25 - 29 27
when calculating the standard deviation:
ReplyDelete1.find the mean
2.subtract the mean from each member
3.square the difference
4.divide the sum by n-1
5.find the square root of this result
in a question like (1)
find the standard deviation for 1,5,4,2,6,2,1,15,3
using the steps:
1.find the mean
1+5+4+2+6+2+1+15+3/9
=39/9
=4.33
2.subtract the mean from each member and 3.square the difference.
=(1-4.33)^+(5-4.33)^+(4-4.33)^+(2-4.33)^+(6-4.33)^+(2-4.33)^+(1-4.33)^+(15-4.33)^+(3-4.33)^
=11.09+0.45+0.11+5.43+2.79+5.43+11.09+113.85+1.77
=152
4. divide the sum by n-1
= 152/(9-1)
= 152/8
= 19.01
5.find the square root of the result
=√ 19.01
= 4.36
therefore the standard deviation for ques.1. is 4.36
following the step lay out above,
ReplyDelete7+8+9+11+12+14+16+17+17+19+20+22
= 172/12
= 14.3
after subtracting 14.3 from each no. the difference was squared an it leaves us with...
53.29 + 39.69 + 28.09 + 10.89 + 5.29 + 0.09 + 2.89 + 7.29 + 7.29 + 22.09 + 32.49 + 59.29
= 288.68
divide by (n-1)
= 288.68/(12-1)
= 26.24
now we find the square root
= 5.12
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ReplyDeletesolution 1
ReplyDelete10-14 12
first find the mean of all the numbers
(10 + 11 + 12 + 13 + 14 + 12)/6
= 61 / 6
= 10.16
after subtracting 10.16 from each number the difference was squared an it leaves us with
0.025 + + 0.7056 + 3.386 + 8.06 + 14.75 + 3.386
= 30.313
standard deviation = square root 30.313/6-1
= 2.46