Final answer:
To find the standard deviation for marks obtained, use the formula: Standard deviation = √Variance. Calculate the variance by finding the mean, subtracting the mean from each value, squaring the result, finding the average of the squared deviations, and finally taking the square root of the variance.
Step-by-step explanation:
To find the standard deviation for marks obtained, we can use the formula:
Standard deviation = √Variance
First, we need to find the variance:
1. Find the mean of the marks obtained by adding up all the values and dividing by the total number of values.
2. Subtract the mean from each value and square the result.
3. Find the average of the squared deviations by adding up all the squared deviations and dividing by the total number of values.
4. Finally, take the square root of the variance to find the standard deviation.
Using the marks obtained and their respective number of students, we can calculate the standard deviation for each range.