Child Development 133 (03, 04,
72, 73 & 74)
Research Methods in Human Development

Hembree            Spring, 2013


Exam Guide #2

Check out the exam handout for more information about the second exam (4/8). You do NOT need to bring a scantron sheet, but you should bring a BLUE BOOK, CALCULATOR and the variance handout with you to the exam.

Introduction to Experimentation (Ch. 9)
internal validity
Types of manipulation (environmental, instructional, invasive)
Pilot studies, manipulation checks
types of variance associated with error (nonsystematic (random error), systematic (confound)
sources of error and ways to reduce
extraneous variables
threats to internal validity: history, maturation, etc (be able to identify)
experimental group/control group
random assignment vs. random sampling
experimenter effects (experimenter characteristics, experimenter expectancies)
participant characteristics (demand characteristics, response bias)
ways to reduce error and increase experimental control (random assignment, elimination of unwanted variables,  constancy, counterbalancing)
double blind experiments
placebo effect/placebo control group

Descriptive Statistics (Ch. 6) (You may bring your variance handout with you to the exam)
descriptive vs. inferential statistics
measures of central tendency (mean, median, mode) - be able to compute and interpret
measures of variability (range, variance, standard deviation)
relationship between variance/standard deviation and the mean
variance (s2) and standard deviation (s) - : be able to compute and interpret
frequency distributions (frequency polygons, histograms)
bar graphs
pictorial representations of data (histograms, bar graphs, frequency polygons) - be able to draw and interpret
z-zcores and the normal distribution - be able to compute and interpret (formula provided)

**bring calculator

Correlational Research (Ch. 7)
correlational studies vs. experiments
scatterplots (be able to interpret)
positive, negative (inverse) linear relationships
correlation coefficients (Pearson r) - be able to interpret
curvilinear relationships
problems with correlations (restricted range, outliers, lack of reliability)
correlation vs. causation and third variables
partial correlations

External validity, generalizability (Supplementary Reading) :
external validity
ecological validity
conceptual and exact replication and importance of replication in science and for external validity
relative benefits of lab and field studies

types of generalization (e.g., population, setting, time of interest)
threats to external validity (based on methods and participants)
ways to improve external validity (be able to identify how to improve external validity in a given study)

difference bewteen interanl and external validity

trade-off between internal and external validity

Short Essay

One of the following questions will be selected for the essay portion of the exam.

  1. Consider the following study:

An educational psychologist wants to investigate whether a particular curriculum intervention is successful in helping children develop math skills. He recruits two 3rd grade classrooms from a local school. In one class, he introduces the new curriculum. The other 3rd grade class uses the regular curriculum. At the end of the intervention period, he tests the children's math skills in both classrooms with an hour-long test. One class is tested before lunch, and the other is tested after lunch, on the same day. The children in the intervention classroom show significantly higher scores on math test. He concludes that his intervention works to improve the 3rd graders' math skills.

  Write an essay addressing the following questions:

  • What is internal validity and what threats to internal validity are present in the study as it has been conducted?

  • Can the researcher conclude that her intervention helped the children (why or why not?) What extraneous variables has the researcher failed to control for? 

  • How could the study be re-designed to reduce the effects of these variables?

  1. Consider the following research question:

A social psychologist believes that children who play video games are more aggressive. Specifically, she believes that the more hours children play video games, the higher the observed aggression on the playground.

Design two studies that test this question: one that is correlational and one that is experimental. Include a brief description of the measures you would use and be sure to identify the independent and dependent variables, if applicable. What is the difference between these two studies in what they allow you to conclude about the relationship between video games and aggression? What are the advantages and disadvantages of these two different designs? 



Send problems, comments or suggestions to:

California State University, Sacramento

College of Education

Department of Child Development

Updated: January 25, 2013

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