The average marks of `10` students in a class was `60` with standard deviation 4. While the average marks of other 10 students was 40 with a standard deviation 6. If all the `20` students are taken together,their standard deviation will be

The average marks of 10 students in a class was 60 with a standard deviation 4 while the average marks of the other ten students was 40 with a standard deviation 6. If all the 20 students are taken together their standard deviation will be

The average marks of 30 students in a class was 80. After two students left out of the class, the average marks of the remaining students was 82. Then the average marks of the two left out students is

Find out the standard deviation of the marks secured by 10 students:

The marks of 10 students in a class are 38, 70, 48,34 ,42, 55 63, 46, 54,44. Find the standard deviation of these marks.

The marks of 10 students in a class are 38, 70, 48,34 ,42, 55 63, 46, 54,44. Find the standard deviation of these marks.

The average marks of 39 students of a class is 50. The marks obtained by 40th student are 39 more than the average marks of all the 40 student are 39 more than the average marks of all the 40 students. Find the mean marks of all the 40 students.

The average marks of 10 students is 30 if 6 marks is added with each students' marks.Then find the new average.

The average marks obtained by 150 students in an examination is 40. If the average marks of passed students is 60 and that of the failed students is 20, then what is the number of students who passed the examination?