In: Math
Grade on Final Exam |
Frequency |
50 |
1 |
60 |
2 |
70 |
3 |
80 |
5 |
90 |
6 |
100 |
3 |
Given is a data on grade on final exam, here we need to determine the mean and standard deviation for the given data.
The data is,
No. | Grade on Final Exam(xi) | Frequency(fi) |
1 | 50 | 1 |
2 | 60 | 2 |
3 | 70 | 3 |
4 | 80 | 5 |
5 | 90 | 6 |
6 | 100 | 3 |
Mean
The mean is a measure of central tendency and the mean gives a fair idea about the value around which the data is clustered. It is given by,
Standard Deviation
The standard deviation gives the measure of spread of the data or how dispersed or data is. It is given by,
Coming back to our problem,
No. | Grade on Final Exam(xi) | Frequency(fi) | xi*fi | ((xi-x̄)^2)*fi |
1 | 50 | 1 | 50 | 961 |
2 | 60 | 2 | 120 | 882 |
3 | 70 | 3 | 210 | 363 |
4 | 80 | 5 | 400 | 5 |
5 | 90 | 6 | 540 | 486 |
6 | 100 | 3 | 300 | 1083 |
Total | 20 | 1620 | 3780 |
The Mean is,
The Standard Deviation is,