風中一匹狼

假設為了瞭解猛犬颱風對乳牛產量的影響，從DHI紀錄中逢基取得10頭泌乳牛在颱風前一週與颱風後一週的每日產乳紀錄如下，是比較颱風對乳牛泌乳量是否有影響?

data typhoon;

input no$ before after @@ ;

diff= before-after;

cards;

025 20 18

028 23 20

076 30 28

084 28 24

096 16 15

111 22 22

123 25 26

131 27 22

146 12 13

150 30 26

;

run;

proc means t prt; /*t檢定*/

var diff;

run;

proc ttest ; /*paired-t檢定*/

paired before*after;

run;

SAS output

The SAS System

The MEANS Procedure

The SAS System

The TTEST Procedure

Difference: before - after