Question

A pathologist counts the numbers of diseased plants in randomly selected areas each 1-meter square on a large field. For 40 such areas the numbers of diseased plants are:

21	18	42	29	81	12	94	117	88	210
44	39	11	83	42	94	2	11	33	91
141	48	12	50	61	35	111	73	5	44
6	11	35	91	147	83	91	48	22	17

Use histograms and boxplots to decide whether there is evidence of skewness or outliers. Use nonparametric tests to find whether it is reasonable to assume the median number of diseased plants per square meter might be 50 (i) without assuming population symmetry, (ii) assuming population symmetry. For these data and the evidence provided by a boxplot and histograms do you consider the latter assumption reasonable?

Answer 1