Answer:
the standard error of data set is 2.628
Step-by-step explanation:
Given the data in the question;
set;
x = 9, 13, 21, 30, 31, 31, 34, 25, 28, 20
To get the standard of Error for this data set, we use the formual
S.E = s / √n
First we determine the mean average;
Mean x' = ∑x / n = ( 9 + 13 + 21 + 30 + 31 + 31 + 34 + 25 + 28 + 20 ) / 10
x' = 242 / 10
Mean x' = 24.2
Next we find the standard deviation s:
x (x-x')²
9 231.04
13 125.44
21 10.24
30 33.64
31 46.24
31 46.24
34 96.04
25 0.64
28 14.44
20 17.64
Total ∑(x-x')² = 621.6
so Variance = ∑(x-x')² / (n-1) = 621.6 / ( 10 - 1 ) = 621.6 / 9
Variance = 69.0667
Standard deviation S = √Variance
Standard deviation S = √69.0667
Standard deviation S = 8.3106
So we substitute into our formula to get the standard of error;
S.E = 8.3106 / √10
S.E = 2.628
Therefore, the standard error of data set is 2.628
