tailieunhanh - principles of epidemiologyin public health practice_part1

phạm vi từ brainFigure khoảng tứ phân vị từ 2,8 tần số lũy tích Một số chương trình phân tích thống kê các phần mềm như sản lượng sản xuất phân phối Thông tin Epi tần số với ba cột: số lượng hoặc tính của các quan sát cho mỗi giá trị của phân phối, tỷ lệ phần trăm của giá trị quan sát cho rằng, và tỷ lệ tích lũy. | Figure Interquartile Range from Cumulative Frequencies 0 5 10 15 20 25 30 35 40 45 50 Some statistical analysis software programs such as Epi Info produce frequency distributions with three output columns the number or count of observations for each value of the distribution the percentage of observations for that value and the cumulative percentage. The cumulative percentage which represents the percentage of observations at or below that value gives you the percentile see Table . Table Frequency Distribution of Length of Hospital Stay Sample Data Northeast Consortium Vancomycin Quality Improvement Project Length of Stay Days Frequency Percent Cumulative Percent 0 1 2 1 3 1 4 1 5 2 6 1 7 1 8 1 9 3 10 5 11 1 12 3 13 1 14 1 16 1 18 2 19 1 22 1 27 1 49 1 Total 30 Summarizing Data Page 2-40 This is trial version A shortcut to calculating Q1 the median and Q3 by hand is to look at the tabular output from these software programs and note which values include 25 50 and 75 of the data respectively. This shortcut method gives slightly different results than those you would calculate by hand but usually the differences are minor. For example the output in Table indicates that the 25th 50th and 75th percentiles correspond to lengths of stay of 7 10 and 14 days not substantially different from the 10 and days calculated above. Summarizing Data Page 2-41 This is trial version Exercise Determine the first and third quartiles and interquartile range for the same vaccination data as in the previous exercises. 2 0 3 1 0 1 2 2 4 8 1 3 3 12 1 6 2 5 1 Check your answers on page 2-61 Summarizing Data Page 2-42 This is trial version .