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1、第二章:定量資料的統(tǒng)計描述引子:變量統(tǒng)計學(xué)醫(yī)學(xué)統(tǒng)計學(xué)研究方法定性資料定量資料統(tǒng)計描述統(tǒng)計推斷隨機性現(xiàn)象概率論數(shù)理統(tǒng)計例2-2抽樣調(diào)查某地120名18~35歲健康男性居民血清鐵含量(μmol/L),數(shù)據(jù)如下:7.428.6523.0221.6121.3121.469.9722.7314.9420.1821.6223.0720.388.4017.3229.6419.6921.6923.9017.4519.0820.5224.1423.7718.3623.0424.2224.1321.5311.0918.8918.2623.2917.6715.3818.6114
2、.2717.4022.5517.5516.1017.9820.1321.0014.5619.8919.8217.4814.8918.3719.5017.0818.1226.0211.3413.8110.2515.9415.8318.5424.5219.2626.1316.9918.8918.4620.8717.5113.1211.7517.4021.3617.1413.7712.5020.4020.3019.3823.1112.6723.0224.3625.6119.5314.7714.3724.7512.7317.2519.0916.7917.1919.
3、3219.5919.1215.3121.7519.4715.5110.8627.8121.6516.3220.7522.1113.1717.5519.2612.6518.4819.8323.1219.2219.2216.7227.9011.7424.6614.1816.52目的:提取該組男性居民血清鐵的分布信息。問題1.該組男性血清鐵是怎樣分布的?問題2.血清鐵主要集中在哪個范圍?頻數(shù)表頻數(shù)分布圖問題4.變異情況?最高?最低?問題3.該組男性血清鐵的平均水平?離散趨勢集中趨勢統(tǒng)計描述:從數(shù)據(jù)資料中獲取信息最基本的方法把握資料基本的特征為統(tǒng)計分析打下基礎(chǔ)頻率
4、表與頻率分布圖描述性統(tǒng)計指標(biāo)統(tǒng)計表與統(tǒng)計圖包括集中趨勢的描述離散趨勢的描述第一節(jié)頻率分布表與頻率分布圖頻數(shù)(frequency):指在一個抽樣資料中,某變量值出現(xiàn)的次數(shù)。(一)離散型定量變量的頻率分布:例2-11998年某山區(qū)96名孕婦產(chǎn)前檢查次數(shù)資料:0,3,2,0,1,5,6,3,2,4,1,0,6,5,1,3,3,…,4,7頻率分布表(frequencydistributiontable):將當(dāng)變量值的個數(shù)較多時,對各變量出現(xiàn)的頻率列表即為頻率分布表,簡稱頻率表。頻率是表示頻數(shù)出現(xiàn)機率的指標(biāo),可用百分?jǐn)?shù)或小數(shù)表示,頻率的和為100%或1。.頻數(shù)表作用
5、:簡化數(shù)據(jù),方便閱讀;顯示數(shù)據(jù)的分布類型和分布特征。頻率直條圖(frequencydistributionfigure):根據(jù)頻數(shù)分布表,以變量值為橫坐標(biāo),頻數(shù)為縱坐標(biāo),繪制的直方圖。圖2-1某地96名婦女產(chǎn)前檢查次數(shù)頻率分布頻率(%)產(chǎn)前檢驗次數(shù)例2-2抽樣調(diào)查某地120名18~35歲健康男性居民血清鐵含量(μmol/L),數(shù)據(jù)如下:7.428.6523.0221.6121.3121.469.9722.7314.9420.1821.6223.0720.388.4017.3229.6419.6921.6923.9017.4519.0820.5224.142
6、3.7718.3623.0424.2224.1321.5311.0918.8918.2623.2917.6715.3818.6114.2717.4022.5517.5516.1017.9820.1321.0014.5619.8919.8217.4814.8918.3719.5017.0818.1226.0211.3413.8110.2515.9415.8318.5424.5219.2626.1316.9918.8918.4620.8717.5113.1211.7517.4021.3617.1413.7712.5020.4020.3019.3823.1112
7、.6723.0224.3625.6119.5314.7714.3724.7512.7317.2519.0916.7917.1919.3219.5919.1215.3121.7519.4715.5110.8627.8121.6516.3220.7522.1113.1717.5519.2612.6518.4819.8323.1219.2219.2216.7227.9011.7424.6614.1816.52求全距列表劃記步驟:寫組段定組距7.428.6523.0221.6121.3121.469.9722.7314.9420.1821.6223.0720.38
8、8.4017.3229.6419.6921.6923.9017.4