Rothamsted Experimental Station In 1919
Ronald Fisher joined
Rothamsted Experimental Station. He was new to agricultural statistics and devised many new procedures. He recruited Mackenzie as his assistant and in 1922 she contributed to two papers: Fisher and Mackenzie (1922) on the analysis of rainfall correlations using harmonic analysis and Fisher, Thornton and Mackenzie (1922) on the analysis of bacterial counts using the Poisson distribution. Fisher and Mackenzie (1923) with its early presentation of the
analysis of variance followed. In these early papers Winifred provided the computing—learning Fisher’s methods by implementing them. By 1924 she was ready to work alone, applying to barley techniques Fisher had devised for wheat. The project was not completed when she left and the work was taken over by
Wishart.
Missionary work in the Congo In 1927 the statistical career of Winifred Alice Mackenzie ended when she married the missionary Trevor Grahame Rupert Tyrrell (1896–1968). Tyrrell was a descendant of the balloonist
Margaret Graham. After war service in the
Royal Army Medical Corps, Tyrrell was ordained and went to the
Belgian Congo with the
Baptist Missionary Society. Winifred joined in this work which was based on the BMS station at
Bolobo established forty years earlier by the explorer and missionary
George Grenfell. Their work was not wholly religious for the Belgian authorities left medicine and education and even the administration of justice to the missions. Winifred learned the local tribal tongues and worked on educating the women and girls—even setting up
Girl Guides units on the English model. ==Personal life==