PSYC 2320 Lecture Notes - Lecture 9: Rock Music, Standard Deviation, Observational Error
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Numerator: systematic error (cid:3046)(cid:3047)(cid:3028)(cid:3041)(cid:3031)(cid:3028)(cid:3045)(cid:3031) (cid:3032)(cid:3045)(cid:3045)(cid:3042)(cid:3045) or (cid:3031)(cid:3033)(cid:3033)(cid:3032)(cid:3045)(cid:3032)(cid:3041)(cid:3030)(cid:3032) (cid:3029)(cid:3032)(cid:3047)(cid:3050)(cid:3032)(cid:3032)(cid:3041) (cid:3040)(cid:3032)(cid:3028)(cid:3041)(cid:3046) (cid:3041)(cid:3048)(cid:3039)(cid:3039) (cid:3046)(cid:3047)(cid:3028)(cid:3041)(cid:3031)(cid:3028)(cid:3045)(cid:3031) (cid:3032)(cid:3045)(cid:3045)(cid:3042)(cid:3045) Error due to an effect of the treatment. There is a difference between control and treatment groups. Noise, natural variation or error, should be minimal due to random assignment and random sampling. Thirty college students were randomly assigned to listen to classical music (n=15) or rock music (n=15) and then given a series of mental tasks. Decision rule: given alpha = 0. 05 and df = n1 1 + n2 1 = 30-2 = 28, reject the null if t obtained exceeds t critical = 2. 048. Reject the null because t obtained = 3. 93 which exceeds t critical = 2. 048. People who listened to classical music performed better than people listening to rock. Sometimes independent t tests take less time than dependent. Able to compare two types of fitness programs. Random assignment helps with this, but it doesn"t get rid of all individual differences.