sorry because I never learn math very serious during my school time. anyone could help me ?
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any know answer for lab Use Measures of Variability - StudentPerfomanceSD
- Thread starter Peter Cheong
- Start date
With very little I know, calculating standard deviation
1. Count of Math Scores
:
Use the COUNT function to find the total number of math scores.
Example formula: =COUNT(A2:A100) (Assuming your math scores are in column A from rows 2 to 100).
2. Count of Math Scores (n-1):
Simply subtract 1 from the count you calculated.
Example formula: =COUNT(A2:A100) - 1.
3. Mean (x̄):
Use the AVERAGE function to find the mean of the math scores.
Example formula: =AVERAGE(A2:A100).
4. Σ(x - x̄)²:
You will need to calculate the squared differences. In a new column (let's say column B), use the formula:
=(A2 - $C$1)^2 (assuming C1 contains the mean).
Drag this formula down to apply it to all scores.
Then use the SUM function to sum the squared differences.
Example formula: =SUM(B2:B100).
5. Σ(x - x̄)² / (n-1):
Divide the sum of squared differences by n−1n−1.
Example formula: =SUM(B2:B100) / (COUNT(A2:A100) - 1).
6. Square Root of Σ(x - x̄)² / (n-1):
Use the SQRT function to find the square root.
Example formula: =SQRT(SUM(B2:B100) / (COUNT(A2:A100) - 1)).
7. Standard Deviation Function =STDEV.S:
You can use Excel's built-in standard deviation function as a check.
Example formula: =STDEV.S(A2:A100).
1. Count of Math Scores
:Use the COUNT function to find the total number of math scores.
Example formula: =COUNT(A2:A100) (Assuming your math scores are in column A from rows 2 to 100).
2. Count of Math Scores (n-1):
Simply subtract 1 from the count you calculated.
Example formula: =COUNT(A2:A100) - 1.
3. Mean (x̄):
Use the AVERAGE function to find the mean of the math scores.
Example formula: =AVERAGE(A2:A100).
4. Σ(x - x̄)²:
You will need to calculate the squared differences. In a new column (let's say column B), use the formula:
=(A2 - $C$1)^2 (assuming C1 contains the mean).
Drag this formula down to apply it to all scores.
Then use the SUM function to sum the squared differences.
Example formula: =SUM(B2:B100).
5. Σ(x - x̄)² / (n-1):
Divide the sum of squared differences by n−1n−1.
Example formula: =SUM(B2:B100) / (COUNT(A2:A100) - 1).
6. Square Root of Σ(x - x̄)² / (n-1):
Use the SQRT function to find the square root.
Example formula: =SQRT(SUM(B2:B100) / (COUNT(A2:A100) - 1)).
7. Standard Deviation Function =STDEV.S:
You can use Excel's built-in standard deviation function as a check.
Example formula: =STDEV.S(A2:A100).