We are interested in studying the effect of a fertilizer on crop yield. Assume that all plots of land in the study are of comparable size. For a random sample of 19 plots of land that used the fertilizer, the mean crop yield was 59 kilograms per hectare, and the standard deviation was 8.1. For a random sample of 18 plots that did not use the fertilizer, the mean crop yield was 23 kilograms per hectare, and the standard deviation was 5.3.

1. a)Test the assumption that the two population variances were equal against the alternative that the population variance is higher for plots of land that used fertilizer.
2. b)What implicit assumptions did we make for this test?