Optimal Experimental Design With Nesting of Persons in Organizations

2013 ◽  
Vol 221 (3) ◽  
pp. 145-159 ◽  
Author(s):  
Gerard J. P. van Breukelen
Keyword(s):  
Repeated Measures ◽  
Optimal Number ◽  
Health Centers ◽  
Randomized Experiments ◽  
Optimal Sample ◽  
Treatment Conditions ◽  
Sampling Cost ◽  
Nested Designs ◽  
Simple Equations ◽  
Number Of Individuals

This paper introduces optimal design of randomized experiments where individuals are nested within organizations, such as schools, health centers, or companies. The focus is on nested designs with two levels (organization, individual) and two treatment conditions (treated, control), with treatment assignment to organizations, or to individuals within organizations. For each type of assignment, a multilevel model is first presented for the analysis of a quantitative dependent variable or outcome. Simple equations are then given for the optimal sample size per level (number of organizations, number of individuals) as a function of the sampling cost and outcome variance at each level, with realistic examples. Next, it is explained how the equations can be applied if the dependent variable is dichotomous, or if there are covariates in the model, or if the effects of two treatment factors are studied in a factorial nested design, or if the dependent variable is repeatedly measured. Designs with three levels of nesting and the optimal number of repeated measures are briefly discussed, and the paper ends with a short discussion of robust design.

Can Seventh Graders Learn Fractions from a Web-Based Pedagogical Agent? Using Comparison Groups Thre Times Over Several Weeks

2011 ◽  
pp. 334-348
Author(s):  
Shannon Adams ◽  
Bruce L. Mann ◽  
Henry Schulz
Keyword(s):  
Web Sites ◽  
Repeated Measures ◽  
Pedagogical Agents ◽  
Pedagogical Agent ◽  
Web Based ◽  
Educational Multimedia ◽  
Treatment Conditions ◽  
Post Test ◽  
Comparison Groups ◽  
Practice Questions

In this study, a Web-based pedagogical agent presented 7th grade students (n = 91) with examples and practice questions involving the multiplication and division of fractions. Pedagogical agents are animated, talking characters that can be made to introduce, guide or otherwise enhance educational Web sites. It was expected that school-age students using moving and talking pedagogical agents would retain more and find more creative solutions to problems than students in the other treatment conditions. A repeated measures-by-occasion research design was used to determine if the movement and or talking by the agent helped them learn to multiply and divide fractions. Results of the analyses showed that students learned from the pre-test to immediate post-test. But there were no effects for either modality (speech vs. text) or agent animation (movement vs. no movement). Consistent with a previous study with 7th grade students using educational multimedia (Mann, Newhouse, Pagram, Campbell, & Schulz, 2002) positive findings from using speech in educational multimedia may only be generalizable to adults and older adolescents. Implications are discussed regarding the instructional design of educational Web sites.

Importance of the Post-Knowledge Delay Interval on Transit Reaction

1983 ◽  
Vol 57 (1) ◽  
pp. 303-307 ◽  
Author(s):  
Reno J. Ramella ◽  
Robert L. Wiegand
Keyword(s):  
Delay Interval ◽  
Repeated Measures ◽  
Interval Data ◽  
Knowledge Of Results ◽  
Treatment Groups ◽  
Treatment Conditions ◽  
Response Interval ◽  
Temporal Location ◽  
Important Time ◽  
Variable Errors

The purpose of this study was to determine if transit reaction or anticipation of coincidence could be improved by allotting more processing time. 120 subjects were randomly assigned to one of six treatment groups. The groups were formed by changing the temporal location of knowledge of results within the research paradigm, specifically to control the possible confounding from the inter-response interval. Data were analyzed via a series of two 6 (treatment conditions) × 5 (trial blocks) factorial analyses of variance, with repeated measures on the last factor for absolute and variable errors. The post-knowledge delay interval was the most important time of the paradigm, and transit reaction was positively related to duration of processing.

Effect of communication skills based group counseling on mothers’ sex dialogue with their adolescent daughters

2018 ◽  
Vol 0 (0) ◽  
Author(s):  
Tayebe Ziaei ◽  
Maryam Ghanbari Gorji ◽  
Naser Behnampour ◽  
Masumeh Rezaei Aval
Keyword(s):  
Communication Skills ◽  
Group Counseling ◽  
Repeated Measures ◽  
Intervention Group ◽  
Health Centers ◽  
Chi Square ◽  
Significant Difference ◽  
Mother And Daughter ◽  
Post Hoc ◽  
And Control

AbstractBackgroundSex dialogue is one of the most critical and challenging topics between mothers and adolescents. The knowledge and skills of mothers in sex dialogue with their daughters are essential. The purpose of this study is to determine the effect of group counseling based on communication skills on mothers through their sex dialogue with their daughters.MethodsA randomized controlled field trial was conducted on 168 couples of mothers and their daughters selected by the stratified matching method and randomly divided into two control and intervention groups. The mothers in the intervention group participated in a communication-based consultation in groups consisting of 6–12 people for 6–7 weekly sessions, each one lasting 60 min. The data collection tool was a Persian-translated questionnaire by Jaccard for sex dialogue between mother and daughter. The data were analyzed using Chi-square (χ2), ANOVA with repeated measures and modified post hoc Bonferroni tests.ResultsThere was a significant difference in the mean score of mother-daughter sex dialogue 1 week after intervention between the intervention (34.48 ± 8.74) and control (40.44 ± 9.49) groups (p = 0.001) and 1 month after the intervention between the intervention (30.41 ± 10.07) and control (42.47 ± 9.62) groups (p < 0.001).ConclusionThrough applying communication skills, an increase in mother-daughter sex dialogue frequency was observed after group counseling. Therefore, it is suggested to promote mother-daughter communication skills by accessing the mothers via schools, health centers and with the aid of midwifery counselors, midwives and other trained caretakers.

Improving Speed and Accuracy of Word Recognition in Reading Disabled Children: An Evaluation of Two Computer Program Variations

1988 ◽  
Vol 11 (4) ◽  
pp. 333-341 ◽  
Author(s):  
Andrew L. Cohen ◽  
Joseph K. Torgesen ◽  
Jeffrey L. Torgesen
Keyword(s):  
Computer Program ◽  
Repeated Measures ◽  
Word Reading ◽  
Relative Effectiveness ◽  
Disabled Children ◽  
Repeated Measures Design ◽  
Reading Vocabulary ◽  
Treatment Conditions ◽  
Speed And Accuracy ◽  
Reading Disabled

The present study investigated the relative effectiveness of two versions of a computer program designed to increase the sight-word reading vocabulary of reading disabled children. One version required children to type words into the computer as part of the practice activity; in the other no typing was involved. Subjects were nine reading disabled students, average age 10 years, 7 months. A repeated-measures design was used to expose all subjects three times to two treatment conditions and a no-practice control condition. Accuracy and speed of reading, as well as spelling accuracy for multisyllable words were measured in pre- and posttests. Both versions of the program proved to be equally effective in improving speed and accuracy of reading words, but the typing version was more effective in increasing spelling accuracy. However, students enjoyed the no-typing version better, and they were able to attain mastery levels for new words on this version faster than on the typing version. Implications of these results for reading software design are considered.

scholarly journals Performance of Trichograma spp in small tomato borer (Neoleucinodes elegantalis Guenée): Pest management with egg parasitoid

2020 ◽  
Vol 42 ◽  
pp. e46915
Author(s):  
José Romário de Carvalho ◽  
Luis Moreira de Araujo Junior ◽  
Dirceu Pratissoli ◽  
Débora Fragoso ◽  
Amanda Túler
Keyword(s):  
Technological Development ◽  
Physicochemical Characteristics ◽  
Egg Parasitoid ◽  
Optimal Number ◽  
Small Fruit ◽  
Fruit Borer ◽  
Alternative Techniques ◽  
Tomato Borer ◽  
Number Of Individuals ◽  
Selection Of

The tomato is a crop of great importance for Brazilian agriculture. Among the most damaging pests, the small tomato borer, Neoleucinodes elegantalis Guenée (Lepidoptera: Crambiadae) has caused great losses, since they directly reach the fruits to be commercialized, being used for its handling a large volume of insecticides. In this way, the use of alternative techniques that help in the management of this pest becomes of great importance. Among them, the use of the egg parasitoid Trichogramma spp. has been promising. Thus, the present study aimed to evaluate the performance of Trichogramma species and/or strains in N. elegantalis by selection of strains. The selection was made based on four lineages maintained in the Nucleus of Scientific and Technological Development in Phytosanitary Management of Pests (NUDEMAFI), being three strains of the species T. pretiosum and one of T. galloi species. The parameters evaluated were percentage of parasitized eggs, egg viability, number of individuals per eggs, sex ratio and number of Trichogramma spp. to be released. The T. galloi (T. g1) showed the best parameters for selection of the strain. Estimating the optimal number of T. g1 in eggs of small-fruit-borer was 82 individuals per egg parasitoid. Therefore, this strain was selected for the management of the small tomato-borer, whose eggs presented favorable physicochemical characteristics for the development of the parasitoid.

scholarly journals Changes in Psychological and Cognitive Outcomes after Green versus Suburban Walking: A Pilot Crossover Study

2019 ◽  
Vol 16 (16) ◽  
pp. 2894 ◽  
Author(s):  
Junia N. de Brito ◽  
Zachary C. Pope ◽  
Nathan R. Mitchell ◽  
Ingrid E. Schneider ◽  
Jean M. Larson ◽  
...  
Keyword(s):  
Negative Affect ◽  
Positive Affect ◽  
Crossover Study ◽  
Repeated Measures ◽  
Digit Span ◽  
Cognitive Outcomes ◽  
Moderate Intensity ◽  
Directed Attention ◽  
Treatment Conditions ◽  
Middle Aged Adults

This study investigated the acute effects of repeated walking sessions within green and suburban environments on participants’ psychological (anxiety and mood) and cognitive (directed-attention) outcomes. Twenty-three middle-aged adults (19 female) participated in a non-randomized crossover study comprised of once-weekly 50-min moderate-intensity walking sessions. Participants walked for three weeks in each of two treatment conditions: green and suburban, separated by a two-week washout period. Eleven participants completed green walking first and 12 suburban walking first. For each walk, we used validated psychological questionnaires to measure pre- and post-walk scores for: (1) mood, evaluated via the Positive and Negative Affect Schedule (PANAS); (2) anxiety, assessed by the State-Trait Anxiety Inventory (STAI-S); and (3) directed-attention, measured using the visual Backwards Digit Span test (BDS). Repeated measures linear mixed models assessed pre- to post-walk changes within-treatment conditions and post-walk contrasts between-treatment conditions. Results indicated that anxiety decreased after green walking and increased after suburban walking (−1.8 vs. +1.1 units, respectively; p = 0.001). For mood, positive affect improved after green walking and decreased after suburban walking (+2.3 vs. −0.3 units, respectively; p = 0.004), and negative affect decreased after green walking and remained similar after suburban walking (−0.5 vs. 0 units, respectively; p = 0.06). Directed-attention did not improve from pre- to post-walk for either condition. Our results suggested that green walking may be more effective at reducing state anxiety and increasing positive affect compared to suburban walking.

A comparison between active- and reactive-hyperaemia-induced brachial artery vasodilation

2006 ◽  
Vol 110 (3) ◽  
pp. 387-392 ◽  
Author(s):  
Jaume Padilla ◽  
Ryan A. Harris ◽  
Alyce D. Fly ◽  
Lawrence D. Rink ◽  
Janet P. Wallace
Keyword(s):  
Endothelial Function ◽  
Brachial Artery ◽  
Repeated Measures ◽  
Reactive Hyperaemia ◽  
High Fat ◽  
Low Fat ◽  
Balanced Design ◽  
Treatment Conditions ◽  
Main Effects ◽  
Fat Meal

The measurement of brachial artery vasodilation in response to a hyperaemic stimulus has been used extensively to assess changes in endothelial function. However, whether or not similar changes occur in response to an active hyperaemic stimulus is unknown. The purpose of the present study was to compare brachial artery vasodilation in response to an active compared with a reactive hyperaemic stimulus following a known perturbation of endothelial function. Eight apparently healthy adults were assigned to four treatment conditions in a counter-balanced design: (i) low-fat meal with active hyperaemic stimulus (LFM-A), (ii) high-fat meal with active hyperaemic stimulus (HFM-A), (iii) low-fat meal with reactive hyperaemic stimulus (LFM-R), and (iv) high-fat meal with reactive hyperaemic stimulus (HFM-R). Meals were ingested at 08:00 hours on each treatment day. Brachial artery vasodilation was assessed via ultrasound 4 h after ingestion of each meal. The active hyperaemic stimulus was induced by 5 min of rhythmic handgrip exercise, whereas reactive hyperaemia was induced by 5 min of forearm occlusion. Brachial artery vasodilation was expressed as the percentage change in diameter from baseline to post-active/reactive hyperaemia. Using a 2×2 repeated measures ANOVA, a significant stimulus×meal interaction (P=0.025) was found. Simple main effects revealed no difference (P=0.541) in brachial artery vasodilation between LFM-A (5.75±1.64%) and HFM-A (6.39±1.45%); however, a significant decrease (P=0.014) in brachial artery vasodilation was found in the HFM-R (4.29±1.64%) compared with the LFM-R (7.18±1.13%) treatment. In conclusion, the measurement of brachial artery vasodilation in response to active hyperaemia did not detect a change in endothelial function following a single perturbation meal, whereas reactive hyperaemia did.

scholarly journals Effect of vibration vs non-vibration foam rolling techniques on flexibility, dynamic balance and perceived joint stability after fatigue

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e8000 ◽  
Author(s):  
Ana María de Benito ◽  
Raúl Valldecabres ◽  
Diego Ceca ◽  
Jim Richards ◽  
Joaquín Barrachina Igual ◽  
...  
Keyword(s):  
Lumbar Spine ◽  
Muscle Fatigue ◽  
Repeated Measures ◽  
Dynamic Balance ◽  
Ankle Dorsiflexion ◽  
Repeated Measures Anova ◽  
Fatigue Protocol ◽  
Ankle Stability ◽  
Treatment Conditions ◽  
Exercise Induced

Background Foam roller and vibration techniques are currently used to assist in recovery after fatigue. The main purpose of this study was to determine the effects of the use of a foam roller with and without vibration on dynamic balance, ankle dorsiflexion, hamstring and lumbar spine flexibility and perceived knee and ankle stability after an induced fatigue protocol. Methods A total of 24 healthy recreationally active participants (17 males and seven females) were recruited to a randomized cross over trial consisting of; no treatment (NT), foam roller treatment (FR) and vibration foam roller treatment (VFR). The assessments included; the Sit & Reach test, Y balance test and post-treatment perceived knee and ankle stability. Measurements were taken after a standardized warm up (baseline) and repeated following an exercise-induced muscle fatigue protocol consisting of repeated lunges until volitional fatigue. The three treatment conditions were assessed on three separate days in a randomized order. A 3 × 3 repeated measures ANOVA was used to investigate differences between the three treatments over the three time points and a one factor repeated measures ANOVA was used to determine any differences between treatments using the Global Rate of Change scale when considering perceived stability. Results FR and VFR conditions both showed a greater ankle dorsiflexion range of motion (ROM) (p < 0.001), greater posteromedial and posterolateral reach distances (p < 0.001) and a better knee and ankle perceived stability (p < 0.001) when compared to the NT condition. A trend toward significance was observed in the hamstring and lumbar spine flexibility (p = 0.074) in both treatment conditions when compared to the NT condition. However, no differences were seen between the FR and VFR conditions. Conclusions Both FR conditions seem to assist in exercise-induced muscle fatigue recovery with improvements in ROM, balance and perceived stability.

scholarly journals Comparison of Eye Movement Desensitization and Reprocessing and Biofeedback/Stress Inoculation Training in Treating Test Anxiety

2012 ◽  
Vol 6 (2) ◽  
pp. 62-72 ◽  
Author(s):  
Rosemary Cook-Vienot ◽  
Raymond J. Taylor
Keyword(s):  
Eye Movement ◽  
Test Anxiety ◽  
Repeated Measures ◽  
Stress Inoculation ◽  
Rational Behavior ◽  
State Trait Anxiety Inventory ◽  
Stress Inoculation Training ◽  
Treatment Conditions ◽  
Autonomic Perception ◽  
Post Hoc

Eye movement desensitization and reprocessing (EMDR) and Biofeedback/Stress Inoculation Training (B/SIT) treatment and no treatment (NT) were compared in reducing test anxiety. Thirty college students with high test anxiety were randomly assigned to each condition. Pre-post assessments were conducted using the Test Anxiety Inventory (TAI), State-Trait Anxiety Inventory (STAI), Rational Behavior Inventory (RBI), and Autonomic Perception Questionnaire (APQ). Treatment therapists were licensed professionals with at least 2 years experience in their respective modality. Statistical analysis using a two-way analysis of variance with repeated measures found significant interactions between time (pre-post) and treatment conditions for all measures except the RBI. Post hoc Newman–Keuls analyses were conducted on the change scores, indicating that both EMDR and B/SIT significantly reduced test anxiety. EMDR generally outperformed B/SIT.

Optimal Survey Design: Lessons from a Stratified Random Sample of Macrobenthos

1979 ◽  
Vol 36 (4) ◽  
pp. 351-361 ◽  
Author(s):  
W. Cuff ◽  
N. Coleman
Keyword(s):  
Random Sample ◽  
Random Sampling ◽  
Survey Design ◽  
Simple Random Sampling ◽  
Optimal Number ◽  
The Common ◽  
Random Survey ◽  
Survey Designs ◽  
Number Of Individuals ◽  
Adequate Data

A stratified random sample of macrobenthos in Western Port (Victoria, Australia) provided adequate data to take an a posteriori look at the efficiency of various random survey designs in terms of their ability to provide precise estimates of the mean number of individuals per taxon, i.e. mean estimates with the smallest possible variance. Emphasis was placed on the efficiency of the stratified simple random sampling design. The analyses showed that bay-wide estimates resulting from various stratified designs would not have been substantially more precise than those from simple random sampling. This conclusion was not influenced by the allocation strategy used in the stratified design. On the other hand, substantial gains in precision could have been made, for the same total number of grab samples, by increasing the number of stations at the expense of the number of grab samples per station. Our data suggested that the optimal number of grab samples per station is only one, contrary to the common practice of multiple grab samples per station. Key words: stratified, random, survey, optimal, macrobenthos, sample, Western Port

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