The marks of a student in 6 tests are `41, 45, 54, 57, 43` and x. If the mean marks of these tests is 48. then standard deviation of these tests is

The marks of a student in 6 tests are 41,45,54,57,43 and x. If the meen marks of these test is 48 .then standard deviation of these tests is

Marks of students in a test is

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

A student scores the following marks in five tests 45, 54, 41, 57, 43. His score is not known for the sixth test. If the mean score is 48 in the six tests, then the standard deviation of the marks in six tests is

A student scores the following marks in five tests 45, 54, 41, 57, 43. His score is not known for the sixth test. If the mean score is 48 in the six tests, then the standard deviation of the marks in six tests is

A student scores the following marks in five tests 45, 54, 41, 57, 43. His score is not known for the sixth test. If the mean score is 48 in the six tests, then the standard deviation of the marks in six tests is

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 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 marks obtained by a student in two unit tests were 65 and 70.Find the minimum marks he should score in the third test to have an average at least 65 marks.