2001
DOI: 10.1037/1082-989x.6.4.387
|View full text |Cite
|
Sign up to set email alerts
|

Effects of study duration, frequency of observation, and sample size on power in studies of group differences in polynomial change.

Abstract: Consider a study in which 2 groups are followed over time to assess group differences in the average rate of change, rate of acceleration, or higher degree polynomial effect. In designing such a study, one must decide on the duration of the study, frequency of observation, and number of participants. The authors consider how these choices affect statistical power and show that power depends on a standardized effect size, the sample size, and a person-specific reliability coefficient. This reliability, in turn,… Show more

Help me understand this report

Search citation statements

Order By: Relevance

Paper Sections

Select...
3
1
1

Citation Types

9
346
1
6

Year Published

2005
2005
2021
2021

Publication Types

Select...
9

Relationship

0
9

Authors

Journals

citations
Cited by 392 publications
(362 citation statements)
references
References 26 publications
9
346
1
6
Order By: Relevance
“…Based on the model defined by Equations (2-4), a total of 11 parameters are specified: four fixed effect coefficients (i.e., µ a1 , µ b1 , µ b2 , and γ ) and seven variances and covariance of random effects (i.e., σ 2 , τ π 00 , τ π 10 , τ π 20 , τ π 11 , τ π 21 , τ π 22 ). Table 1 presents the population parameter values specified based on previous studies (see e.g., [39]). …”
Section: Data Generationmentioning
confidence: 99%
See 1 more Smart Citation
“…Based on the model defined by Equations (2-4), a total of 11 parameters are specified: four fixed effect coefficients (i.e., µ a1 , µ b1 , µ b2 , and γ ) and seven variances and covariance of random effects (i.e., σ 2 , τ π 00 , τ π 10 , τ π 20 , τ π 11 , τ π 21 , τ π 22 ). Table 1 presents the population parameter values specified based on previous studies (see e.g., [39]). …”
Section: Data Generationmentioning
confidence: 99%
“…Given that the growth rate in the first piece is 0.6, following Raudenbush and Liu's [39] effect size equation, the growth rate of the second piece is set to be 0.44 for the medium change condition and 0.54 for the small change condition.…”
Section: Magnitude Of Change In the Growth Ratementioning
confidence: 99%
“…The variances of b 00 j , c 00k , and their covariance depend on the values of ICC and correlation. j0 and c 10k were set to be half of the variances of b 0 j0 and c 00k as the variances of slopes are often smaller than those of intercepts (Raudenbush & Liu, 2001). The covariances between random intercepts and random slopes (b 0 j0 and b 1 j0 ; c 00k and c 10k ) were set to zero.…”
Section: Model Used To Generate Datamentioning
confidence: 99%
“…Presented in Table 1 are the generating distribution of the residuals in random intercepts and slopes (b 0 j0 , b 1 j0 , c 00k , c 10k ) by correlation and ICC values. Using τ as the symbol for variance, the ICC is calculated as (Raudenbush & Liu, 2001). The covariances between random intercepts and random slopes (b 0 j0 and b 1 j0 ; c 00k and c 10k ) were set to zero.…”
Section: Model Used To Generate Datamentioning
confidence: 99%