Experimental design. Variables Independent variable Dependent variable Levels Responses.

Präsentation zum Thema: "Experimental design. Variables Independent variable Dependent variable Levels Responses."—  Präsentation transkript:

1 Experimental design

2 Variables Independent variable Dependent variable Levels Responses

3 Example 1 Subjects are given two types of constructions and are asked to decide whether the given sentence is grammatical: (1)a. I gave him it.Construction 1 b.I gave her the book. c.… (2)a.I gave to him it.Construction 2 b.I gave to her the note you sent me. c.…

4 Example 1 IV (two conditions)DV (forced choice task) Construction 1 Construction 2 a. grammatical b. ungrammatical

5 Example 2 Subjects are asked to complete copular sentences with a relative clause. The predicate nominals of the copular clauses belong to three different semantic types: (1) animate/human (2) inanimate/object (3) place. (1)a.This is the man __ b.This is the ball __ c.This is the place __

6 Example 2 IVDV 1. This is the man __ 2. This is the ball __ 3. This is the place __ a. SUBJ relative clause b. DO relative clause c. IO relative clause d. OBL relative clause e. GEN relative clause

7 Example 2 IVDV 1. This is the man __ 2. This is the thing __ 3. This is the place __ a. SUBJ relative clause b. DO relative clause c. IO relative clause d. OBL relative clause e. GEN relative clause 1. I saw the man __ 2. I saw the thing __ 3. I saw the place __

8 Example 2 Condition 1 Condition 2 SUBJ 3.5 DO 3.2 IO 2.7 OBL 2.2 GEN 0.6 SUBJ 2.5 DO 3.8 IO 3.2 OBL 0.5 GEN 0.5

9 Types of data Nominal/categorical data Ordinal data Interval data

10 Type of analysis Correlational analysis Difference test

11 Type of analysis Correlational test Difference test Pearson‘s r Kendall‘s tau T-test ANOVA

12 Confound variables (1)… the man who talked to Mary. (2)… the car that caused the accident. (3)… the man who Mary talked to. (4)… the car that Peter bought.

13 Confound variables (1)… the man who talked to Mary. (2)… the car that caused the accident. (3)… the man who Mary talked to. (4)… the car that Peter bought.

14 Confound variables Control Randomization

15 Sampling Simple random sampling Stratified random sampling Systematic sampling Cluster sampling

16 Related and independent design Within subjects design – related design – repeated measures design Between subjects design – unrelated design – independent design

17 Advantages of within subjects design Reduction of inter-individual differences Fewer subjects

18 Disdvantages of within subjects design Subjects recognize the purpose of the study. Subjects get tired, frustrated, excited. Subjects get habituated to the task. Responses to IVs/conditions can influence each other:

19 Counterbalancing ABBA AB - BA Counterbalancing serves to eliminate the ordering effect.

20 Counterbalancing 1.ABC 2.ACB 3.BAC 4.CAB 5.BCA 6.CBA

21 Experimental design A child language researcher wants to find out if the meaning of the head of a relative clause influences the interpretation of the acquisition of relative clauses in early child speech. Specifically, he wants to know if animate and inanimate head nouns affect children’s interpretation of relative clauses. In this study, he concentrats on the two most frequent types of relative clauses in which the subject and object are relativized (i.e. expressed by the relative pronoun).

22 Experimental design (1)Das ist der Mann, der das Mädchen gestern gesehen hat. (2)Das ist der Mann, den das Mädchen gestern gesehen hat. (3)Das ist der Ball, der das Mädchen am Kopf getroffen hat. (4)Das ist der Ball, den das Mädchen mit dem Kopf getroffen hat.

23 Experimental design (1)Das ist der Mann, der das Mädchen gestern gesehen hat. (2)Das ist der Mann, den das Mädchen gestern gesehen hat. (3)Das ist der Ball, der das Mädchen am Kopf getroffen hat. (4)Das ist der Ball, den das Mädchen mit dem Kopf getroffen hat.

24 Experimental design Animate headInanimate head Subject Object