 After Karl Pearson died in 1934, David returned to the Biometrics laboratory to work with Jerzy Neyman, submitting her four most recently published papers as her PhD thesis, and earned a doctorate in 1938.Working for Karl Pearson, F. N. David computed solutions to complicated multiple integrals, and the distribution of the correlation coefficients.As a result, her first book was released in 1938, called "Tables of the Correlation Coefficient".