Directions: The answer to the following question is a single digit integer ranging from 0 to 9. Enter the correct digit in the box given below.
How many open chain structures are possible for N-Methly butanamine (including it) that are referred to as metamers.


For a statistical data \( x_1, x_2, \dots, x_{10} \) of 10 values, a student obtained the mean as 5.5 and \[ \sum_{i=1}^{10} x_i^2 = 371. \] He later found that he had noted two values in the data incorrectly as 4 and 5, instead of the correct values 6 and 8, respectively.
The variance of the corrected data is: