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Question. This is a mixed design one part Drug uses the old independent measures method – between conditions with within conditions as error term The other part is
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Question • This is a mixed design one part • Drug uses the old independent measures method – between conditions with within conditions as error term • The other part is • 2) Question (forced choice v free response) is repeated measures – find within subjects then subtract between conditions and interaction to get error (SSsubject x condition)
SSwithin_drug Part 1 – Independent measures - Drug Subj Means 10.5 7 12 12 9.5 9 10 14.5 5 7.5 9.5 8.5 6 4.5 10 8.5 - SSwithin_drug Collapse subject (mean) over Question Now mean within drug (within Ritalin, etc..) Then (Subj Mean – Mean (Ritalin) Drug)2 Sum Multiply times number Levels_Question - 2 Or number of x’s within the Subj Mean (in red) df = # of subj means (blue) with Ritalin Mean – 1 (3) X number of drug groups (4) = 12
SSbetween_drug Part 1 – Independent measures - Drug Subj Means 10.5 7 12 12 9.5 9 10 14.5 5 7.5 9.5 8.5 6 4.5 10 8.5 _ SSbetween_drug 1)Collapse subject (mean) over Question 2)Now mean within Drug type (within Ritalin, etc..) 3)Then (Mean (Ritalin) Drug – Grand Mean)2 Then (Mean (Adderall) Drug – Grand Mean)2 4)Sum 5)Multiply times number Levels_Question (2) X number of Subj Means within Mean (Ritalin) Drug (4)=8 Or number of x’s within Subj Mean (in red) times (2) x’s within Mean (Ritalin) Drug (in blue) (4) = 8 df = number of drug groups (4) – 1 = 3
Between is of interest Within is the error term
Part 2 – Repeated measures - Question Within_subjects Is made up of Between_groups Interaction Error Term
SSwithin_subjects - Question Sub ForcedChoice Free Resp Drug X - mean Sub 1 X - mean Sub 1 Mean Sub 1 Squared Squared 1 13 8 Ritalin 6.25 6.25 2.5 -2.5 10.5 2 6 8 Ritalin 3 12 12 Ritalin 4 11 13 Ritalin 5 11 8 Adderall 6 6 12 Adderall 7 12 8 Adderall 8 14 15 Adderall 9 8 2 Caffeine 10 9 6 Caffeine 11 13 6 Caffeine 12 10 7 Caffeine 13 10 2 Control 14 3 6 Control 15 14 6 Control 16 8 9 Control Sum • Mean within Sub • Subtract each x from Mean Sub • Square each • Sum all df = Number of Levels of Question (1) – 1 X Number of Subjects (16) = (16)
SSbetween_condition Question Sub ForcedChoice Free Resp Drug Squared Squared Mean Forced Choice Mean Free Resp GrandMean 1 13 8 Ritalin 8 1 10 9 1 2 6 8 Ritalin 3 12 12 Ritalin 4 11 13 Ritalin 5 11 8 Adderall 6 6 12 Adderall 7 12 8 Adderall 8 14 15 Adderall 9 8 2 Caffeine 10 9 6 Caffeine 11 13 6 Caffeine 12 10 7 Caffeine 13 10 2 Control 14 3 6 Control Mean Forced Choice Minus GrandMean Mean Free Resp Minus GrandMean 15 14 6 Control 16 8 9 Control 1 -1 df = two levels of the factor – 1 = 1 • Mean within Question • Subtract each Mean Question from Grand Mean • Square each • Sum • Multiply times number of x’s within each mean (16) Sum
SSdrug x question = SSdrug_question – SSdrug - SSquestion Forced Choice Drug Type Mean- GrandMean Forced Choice Drug Type Mean- GrandMean Sub ForcedChoice Free Resp Drug GrandMean 1 13 8 Ritalin 9 2 6 8 Ritalin 3 12 12 Ritalin 1.25 1.5 4 11 13 Ritalin 5 11 8 Adderall 6 6 12 Adderall 7 12 8 Adderall 8 14 15 Adderall 9 8 2 Caffeine 10 9 6 Caffeine 11 13 6 Caffeine 12 10 7 Caffeine 13 10 2 Control 14 3 6 Control 15 14 6 Control 16 8 9 Control Free Resp Drug Type Mean Forced Choice Drug Type Mean 10.5 10.25 Need to find SSdrug_question first • Take mean of within each Question (Forced Choice) and within each Drug type (Ritalin) • Subtract each mean from Grand Mean • Square and sum • Multiply times the number of x’s into each mean (4) • That equals SSsub_drug • SSdrug_x_question = SSsub_drug – SSdrug – SSquestion • You already have SSdrug from SSbetween_drug, and SSquestion from SSbetween_question df = Number of Levels of Question (2) – 1 = 1
Now you need to figure out MSerror, which is MSerror = SSwithin_sub – SSbetween_question – SSquestion_x_drug Since you have all these you just subtract them Since Within_subjects Is made up of Between_groups Interaction Error Term df of Between_groups, interaction and error term should add up to equal within_subjects So df_error = df_within – df_between_groups - interaction
Between is of interest Within is the error term Error for both Between_question and interaction