tailieunhanh - How to Display Data- P9

How to Display Data- P9:The best method to convey a message from a piece of research in health is via a fi gure. The best advice that a statistician can give a researcher is to fi rst plot the data. Despite this, conventional statistics textbooks give only brief details on how to draw fi gures and display data. | to U E _c ui v ZE a nnnnnn WW IWUUUUUl IZ5 OJ E 1-70- T AAAWl jjjj- WWW 8 He Mete wuuuuuut b Men n 77 4 Women n 145 Figure Dot plots of height of patients in the leg ulcer trial in metres n 222 3 a for all patients and b by sex. Displaying quantitative data 33 The heights in metres of the first 10 men enrolled into the leg ulcer study are as follows Taking thefirut tiumberoftlte seriesabove thestemis tlteleu. is8 and the freqosncyfiae that row is 1 Freqtene u Stem Sesf 1 8 Taking the next height Frequency Stem Leaf 1 8 1 8 And the next height Frequency Stem Leaf 2 83 1 8 And so on. Frequency Stem Leaf 1 5 6 835880 2 85 1 3 Figure shows a stem an d leaf plot for the heights of all 77 men. However in this plot il e an be seen that there is a lot of bunching particularly for the stem. In this case and for other plots where there are few stems and many individualsin eachstem thestems catibe further divided such that each sSam bin esefrrsenSt a smstler ieiisrvdi. FcrthepresenScase the stems cvnVedivtUadforepreaenS sntcrvalu offem In all thesiemasidreuf piots above the iraues are acaanoeainflsa oedec of how the valuecocous css are doba aeries ondthesr are fiiown sis asfday come stem coV ieaf wa reavmmond oudasitig thevrfusrin 34 How to Display Data Frequency Stem Leaf 1 7 42 25 2 1 .9 7 5833385 58 8 38883888033553380008883858883350 8535333358888035000003800 31 Figure Stem and leaf plot of the height of the male 3g ulcer patient with stems of size 10 cm h 11 c Frequency eastern Le .f 1 i- 7 3 1- 333 4 - 5885 18 1- 303330333300033303 24 i- 858888888888558888858885 15 1- 333330300000300 10 i- 8555888858 1 1- 31 Figure Stem and leaf plot of the height of the male leg uleet gefientf wfg ctems of size 5 cm n 11 .