Stephen Olejnik
Biographic Data
| ID | 5180589 |
|---|---|
| NAME | Stephen Olejnik |
| GIVEN NAMES | Stephen |
| FAMILY NAME | Olejnik |
| SIGNATURE | OLEJNIK S |
| AFFILIATIONS | University of Georgia |
| VERIFIED | No |
| TOTAL WORKS | 18 |
| TOTAL CITATIONS | 48 |
| WORKS AS AUTHOR | 18 |
| WORKS AS EDITOR | 0 |
| FIRST PUBLICATION YEAR | 1975 |
| LATEST PUBLICATION YEAR | 2005 |
| H-INDEX | 3 |
The Tabu Search Procedure
The effectiveness of the Tabu variable selection algorithm, to identify predictor variables related to a criterion variable, is compared with the stepwise variable selection method and the all possible regression approach. Considering results obtained from previous research, Tabu is more successful in identifying relevant variables than the stepwise method, and the adjusted R⊃2 and the Mallow Cp criteria from all possible regression models for ce…
Bias and Precision of Measures of Association for a Fixed-Effect Multivariate Analysis of Variance Model
The sampling distributions of five popular measures of association with and without two bias adjusting methods were examined for the single factor fixed-effects multivariate analysis of variance model. The number of groups, sample sizes, number of outcomes, and the strength of association were manipulated. The results indicate that all five unadjusted measures of association can be extremely biased when sample sizes are small and the bias increas…
Generalized Eta and Omega Squared Statistics
The editorial policies of several prominent educational and psychological journals require that researchers report some measure of effect size along with tests for statistical significance. In analysis of variance contexts, this requirement might be met by using eta squared or omega squared statistics. Current procedures for computing these measures of effect often do not consider the effect that design features of the study have on the size of t…
Treatment Of Missing Data At The Second Level Of Hierarchical Linear Models
The problem of missing data at the second level of a two-level hierarchical data structure was investigated. Using data generated to simulate the 1982 High School and Beyond data set, five missing data treatments—listwise deletion, overall mean substitution, group mean substitution, the expectation maximization (EM) algorithm, and multiple imputation—were examined under four manipulated conditions: number of Level 2 variables, Level 2 sample size…
Sample Size Tables for Correlation Analysis with Applications in Partial Correlation and Multiple Regression Analysis
Tables for selecting sample size in correlation studies are presented. Some of the tables allow selection of sample size so that r (or r2, depending on the statistic the researcher plans to interpret) will be within a target interval around the population parameter with probability .95. The intervals are ±.05, ±.10, ±.15, and ±.20 around the population parameter. Other tables allow selection of sample size to meet a target for power when conducti…
Vocabulary Tricks
This quasi-experimental study compared the effects of morphemic and contextual analysis instruction (MC) with the effects of textbook vocabulary instruction (TV) that was integrated into social studies textbook lessons. The participants were 157 students in eight fifth-grade classrooms. The results indicated that (a) TV students were more successful at learning textbook vocabulary; (b) MC students were more successful at inferring the meanings of…
Teaching morphemic and contextual analysis to fifth‐grade students
S This study explored the effects of instruction in morphemic analysis (select prefixes) and contextual analysis (select context clue types). Four classes of fifth‐grade students were assigned to a morphemiconly, context‐only, or combined morphemic‐context experimental group or to an instructed control group. Following twelve 50‐minute lessons, students were tested on their ability to recall the meanings of words used to teach the morphemic and c…
The Efficacy of Two Improvement-Over-Chance Effect Sizes for Two-Group Univariate Comparisons Under Variance Heterogeneity and Nonnormality
The efficacy of two improvement-over-chance or I effect sizes, derived from predictive discriminant analysis (PDA) and logistic regression analysis (LRA), was investigated for two-group univariate mean comparisons. Data were generated under selected levels of population separation, variance pattern, sample size, and distribution shape. Based on the accuracy of sample estimates, both I indices are acceptable under optimal conditions except when bo…
Measures of Effect Size for Comparative Studies
Determining Sample Size for Accurate Estimation of the Squared Multiple Correlation Coefficient
While several resources are available to help researchers determine the minimum sample size needed to achieve target power for a wide variety of hypothesis tests, such resources are generally not available for determining the sample size when accurate parameter estimation is of interest. Sample size tables and procedures used to determine sample size for hypothesis tests should not be used for estimation because providing evidence that a paramete…
Statistical Practices of Educational Researchers
Articles published in several prominent educational journals were examined to investigate the use of data analysis tools by researchers in four research paradigms: between-subjects univariate designs, between-subjects multivariate designs, repeated measures designs, and covariance designs. In addition to examining specific details pertaining to the research design (e.g., sample size, group size equality/inequality) and methods employed for data a…
The Role of Context and Dictionary Definitions on Varying Levels of Word Knowledge
Les auteurs ont examine les facteurs de contexte et de definitions qui determinent si les etudiants de premier cycle apprennent des mots inconnus sans enseignement prealable, et dans quelle mesure. Des tests ont ete effectues pour evaluer les variations de niveau dans la connaissance de mots nouveaux. Les resultats montrent qu'il n'y a pas d'interaction entre les variables de contexte et de definition
A Sas/Iml Program for Applying the James Second-Order Test in Two-Factor Fixed-Effect Anova Models
The SAS/IML computer program package performs the James second-order procedure in two-factor fixed-effect ANOVA models. Researchers can conveniently test main effects and interaction effects by applying the James second-order test, which can be applied regardless of the homogeneity restriction
The Relation between Self-Selected Study Processes and Test Performance
This investigation used correlational methods in a realistic setting to examine the relation between test performance and four study processes that subjects self-selected: encoding, word meaning, organizing, and executive control. The participants were 123 university freshmen who were trained over a 5-week period to use a variety of study strategies. Then, for 5 weeks following training, subjects self-selected study processes and the strategies a…
Communicating with dying children and their siblings
Recognition that children over age 4 with fatal illnesses generally anticipate their death has prompted more open communication between them and the adults caring for them. We investigated factors influencing the extent and success of such communication between parents, dying children, and their siblings, using data provided by 77 mothers who are members of the Compassionate Friends organization. We found that those mothers who talked more freely…
Tests of Variance Equality When Distributions Differ in Form and Location
Type I error rates and power were estimated for ten tests of variance equality under various combinations of the following factors: similar and dissimilar distributional forms, equal and unequal means, and equal and unequal sample sizes. The results indicated that four tests had appropriate Type I error rates for most of the distribution combinations. Of these tests, O'Brien's test tended to be most powerful with equal-sized samples and with an i…
Implementing the Welch-James Procedure with Factorial Designs
The Welch-James procedure may be used to test hypotheses on means, when independent samples from populations with heterogeneous variances are available. Until recently the complexity of the available presentations of this procedure limited the application of this procedure. To resolve this state of affairs, summation formulas for the Welch-James procedure are presented for the 2 x 2 design. In addition, matrix formulas that permit routine applica…
An Empirical Investigation Comparing the Effectiveness of Four Scoring Strategies on the Kuder Occupational Interest Survey Form DD
Responses to the Kuder Occupational Interest Survey by 3983 males from nine occupational groups provided the data to compare the accuracy of four scoring strategies: lambda coefficients, currently used by the test publisher, chi-square weights and two applications of multiple discriminant analysis. An analysis of variance test of the percentage of individuals correctly identified by each technique indicated that no statistically significant diffe…
Teaching morphemic and contextual analysis to fifth‐grade students
S This study explored the effects of instruction in morphemic analysis (select prefixes) and contextual analysis (select context clue types). Four classes of fifth‐grade students were assigned to a morphemiconly, context‐only, or combined morphemic‐context experimental group or to an instructed control group. Following twelve 50‐minute lessons, students were tested on their ability to recall the meanings of words used to teach the morphemic and c…
Vocabulary Tricks
This quasi-experimental study compared the effects of morphemic and contextual analysis instruction (MC) with the effects of textbook vocabulary instruction (TV) that was integrated into social studies textbook lessons. The participants were 157 students in eight fifth-grade classrooms. The results indicated that (a) TV students were more successful at learning textbook vocabulary; (b) MC students were more successful at inferring the meanings of…
The Role of Context and Dictionary Definitions on Varying Levels of Word Knowledge
Les auteurs ont examine les facteurs de contexte et de definitions qui determinent si les etudiants de premier cycle apprennent des mots inconnus sans enseignement prealable, et dans quelle mesure. Des tests ont ete effectues pour evaluer les variations de niveau dans la connaissance de mots nouveaux. Les resultats montrent qu'il n'y a pas d'interaction entre les variables de contexte et de definition
The Relation between Self-Selected Study Processes and Test Performance
This investigation used correlational methods in a realistic setting to examine the relation between test performance and four study processes that subjects self-selected: encoding, word meaning, organizing, and executive control. The participants were 123 university freshmen who were trained over a 5-week period to use a variety of study strategies. Then, for 5 weeks following training, subjects self-selected study processes and the strategies a…
An Empirical Investigation Comparing the Effectiveness of Four Scoring Strategies on the Kuder Occupational Interest Survey Form DD
Responses to the Kuder Occupational Interest Survey by 3983 males from nine occupational groups provided the data to compare the accuracy of four scoring strategies: lambda coefficients, currently used by the test publisher, chi-square weights and two applications of multiple discriminant analysis. An analysis of variance test of the percentage of individuals correctly identified by each technique indicated that no statistically significant diffe…
Implementing the Welch-James Procedure with Factorial Designs
The Welch-James procedure may be used to test hypotheses on means, when independent samples from populations with heterogeneous variances are available. Until recently the complexity of the available presentations of this procedure limited the application of this procedure. To resolve this state of affairs, summation formulas for the Welch-James procedure are presented for the 2 x 2 design. In addition, matrix formulas that permit routine applica…
Tests of Variance Equality When Distributions Differ in Form and Location
Type I error rates and power were estimated for ten tests of variance equality under various combinations of the following factors: similar and dissimilar distributional forms, equal and unequal means, and equal and unequal sample sizes. The results indicated that four tests had appropriate Type I error rates for most of the distribution combinations. Of these tests, O'Brien's test tended to be most powerful with equal-sized samples and with an i…
Communicating with dying children and their siblings
Recognition that children over age 4 with fatal illnesses generally anticipate their death has prompted more open communication between them and the adults caring for them. We investigated factors influencing the extent and success of such communication between parents, dying children, and their siblings, using data provided by 77 mothers who are members of the Compassionate Friends organization. We found that those mothers who talked more freely…
The Relation between Self-Selected Study Processes and Test Performance
This investigation used correlational methods in a realistic setting to examine the relation between test performance and four study processes that subjects self-selected: encoding, word meaning, organizing, and executive control. The participants were 123 university freshmen who were trained over a 5-week period to use a variety of study strategies. Then, for 5 weeks following training, subjects self-selected study processes and the strategies a…
A Sas/Iml Program for Applying the James Second-Order Test in Two-Factor Fixed-Effect Anova Models
The SAS/IML computer program package performs the James second-order procedure in two-factor fixed-effect ANOVA models. Researchers can conveniently test main effects and interaction effects by applying the James second-order test, which can be applied regardless of the homogeneity restriction
The Role of Context and Dictionary Definitions on Varying Levels of Word Knowledge
Les auteurs ont examine les facteurs de contexte et de definitions qui determinent si les etudiants de premier cycle apprennent des mots inconnus sans enseignement prealable, et dans quelle mesure. Des tests ont ete effectues pour evaluer les variations de niveau dans la connaissance de mots nouveaux. Les resultats montrent qu'il n'y a pas d'interaction entre les variables de contexte et de definition
Statistical Practices of Educational Researchers
Articles published in several prominent educational journals were examined to investigate the use of data analysis tools by researchers in four research paradigms: between-subjects univariate designs, between-subjects multivariate designs, repeated measures designs, and covariance designs. In addition to examining specific details pertaining to the research design (e.g., sample size, group size equality/inequality) and methods employed for data a…
Measures of Effect Size for Comparative Studies
Determining Sample Size for Accurate Estimation of the Squared Multiple Correlation Coefficient
While several resources are available to help researchers determine the minimum sample size needed to achieve target power for a wide variety of hypothesis tests, such resources are generally not available for determining the sample size when accurate parameter estimation is of interest. Sample size tables and procedures used to determine sample size for hypothesis tests should not be used for estimation because providing evidence that a paramete…
The Efficacy of Two Improvement-Over-Chance Effect Sizes for Two-Group Univariate Comparisons Under Variance Heterogeneity and Nonnormality
The efficacy of two improvement-over-chance or I effect sizes, derived from predictive discriminant analysis (PDA) and logistic regression analysis (LRA), was investigated for two-group univariate mean comparisons. Data were generated under selected levels of population separation, variance pattern, sample size, and distribution shape. Based on the accuracy of sample estimates, both I indices are acceptable under optimal conditions except when bo…
Teaching morphemic and contextual analysis to fifth‐grade students
S This study explored the effects of instruction in morphemic analysis (select prefixes) and contextual analysis (select context clue types). Four classes of fifth‐grade students were assigned to a morphemiconly, context‐only, or combined morphemic‐context experimental group or to an instructed control group. Following twelve 50‐minute lessons, students were tested on their ability to recall the meanings of words used to teach the morphemic and c…
Generalized Eta and Omega Squared Statistics
The editorial policies of several prominent educational and psychological journals require that researchers report some measure of effect size along with tests for statistical significance. In analysis of variance contexts, this requirement might be met by using eta squared or omega squared statistics. Current procedures for computing these measures of effect often do not consider the effect that design features of the study have on the size of t…
Treatment Of Missing Data At The Second Level Of Hierarchical Linear Models
The problem of missing data at the second level of a two-level hierarchical data structure was investigated. Using data generated to simulate the 1982 High School and Beyond data set, five missing data treatments—listwise deletion, overall mean substitution, group mean substitution, the expectation maximization (EM) algorithm, and multiple imputation—were examined under four manipulated conditions: number of Level 2 variables, Level 2 sample size…
Sample Size Tables for Correlation Analysis with Applications in Partial Correlation and Multiple Regression Analysis
Tables for selecting sample size in correlation studies are presented. Some of the tables allow selection of sample size so that r (or r2, depending on the statistic the researcher plans to interpret) will be within a target interval around the population parameter with probability .95. The intervals are ±.05, ±.10, ±.15, and ±.20 around the population parameter. Other tables allow selection of sample size to meet a target for power when conducti…
Vocabulary Tricks
This quasi-experimental study compared the effects of morphemic and contextual analysis instruction (MC) with the effects of textbook vocabulary instruction (TV) that was integrated into social studies textbook lessons. The participants were 157 students in eight fifth-grade classrooms. The results indicated that (a) TV students were more successful at learning textbook vocabulary; (b) MC students were more successful at inferring the meanings of…
The Tabu Search Procedure
The effectiveness of the Tabu variable selection algorithm, to identify predictor variables related to a criterion variable, is compared with the stepwise variable selection method and the all possible regression approach. Considering results obtained from previous research, Tabu is more successful in identifying relevant variables than the stepwise method, and the adjusted R⊃2 and the Mallow Cp criteria from all possible regression models for ce…
Bias and Precision of Measures of Association for a Fixed-Effect Multivariate Analysis of Variance Model
The sampling distributions of five popular measures of association with and without two bias adjusting methods were examined for the single factor fixed-effects multivariate analysis of variance model. The number of groups, sample sizes, number of outcomes, and the strength of association were manipulated. The results indicate that all five unadjusted measures of association can be extremely biased when sample sizes are small and the bias increas…
Mathematics (13 works) · Statistics (13 works) · Computer Science (9 works) · Econometrics (9 works) · Psychology (9 works) · Sample size determination (7 works) · Sample (material) (6 works) · Advanced Statistical Methods and Models (5 works) · Analysis of variance (5 works) · Advanced Statistical Modeling Techniques (4 works)