Psychology 506 - Midterm Study Guide

Briefly describe at least four different types of norms used for standardizing tests.

Age norms: average performance of different samples of test-takers who were at various ages when the test was administered. Grade norms: the average test performance of test-takers in a given school grade. National norms: derived from a normative sample that was nationally representative of the population at the time the norming study was conducted. Local norms: provide normative information with respect to the local population's performance on some test.

Briefly define measures of central tendency. Briefly discuss how to obtain the mean median and mode of a group of scores.

Central tendency is a statistic that indicates the average or midmost score between the extreme scores in a distribution; mean - sum of the observations (or test scores), in this case divided by the number of observations; median - the middle score in a distribution (particularly useful when there are outliers, or extreme scores in a distribution); mode - the most frequently occurring score in a distribution (when two scores occur with the highest frequency a distribution is said to be bimodal).

Briefly describe and give the formula for the Content Validity Ratio (CVR).

Content validity is a judgment of how adequately a test samples behavior representative of the universe of behavior that the test was designed to sample. (Do the test items adequately represent the content that should be included in the test?) The CVR is an item statistic that is useful in the rejection or retention of specific items. The formula is: CVR = [n - (N/2) / (N/2)]

Briefly describe and compare convergent and discriminant validity.

Convergent evidence - scores on the test undergoing construct validation tend to correlate highly in the predicted direction with scores on older, more established, tests designed to measure the same (or a similar) construct. Discriminant evidence - validity coefficient showing little relationship between test scores and other variables with which scores on the test should not theoretically be correlated

Briefly define dynamic versus static traits and what reliability method would be best for tests designed to measure these traits.

Dynamic traits are ones that are capable of change as a result of situational and cognitive experiences (i.e., anxiety). The best measure of reliability for dynamic traits is internal consistency. Static traits are ones that remain fixed or stationary (i.e., intelligence). The best measure of reliability for static traits is test-retest or alternate-forms.

Briefly discuss the rights of test takers with regard to test findings or results.

In the past test-takers were often not told of diagnostic findings or anything that might hurt their self-image. Currently, giving information about test performance to examinees is ethically and legally mandated and may be useful from a therapeutic perspective as well. Test-takers have a right to know about test findings and recommendations. Test-users should sensitively inform test-takers of the purpose of the test, the meaning of the score relative to those of other test-takers, and the possible limitations and margins of error of the test. Test-takers have a right to know why they are being evaluated, how the test data will be used, and what (if any) information will be released to whom.

Briefly describe the different statistical methods for calculating the internal consistency reliability of a test.

Inter-item consistency: The degree of relatedness of items on a test. Able to gauge the homogeneity of a test. Kuder-Richardson formula 20: statistic of choice for determining the inter-item consistency of dichotomous items Coefficient alpha: mean of all possible split-half correlations, corrected by the Spearman-Brown formula. The most popular approach for internal consistency. Values range from 0 to 1. Average Proportional Distance (APD): Focuses on the degree of difference between scores on test items. It involves averaging the difference between scores on all of the items and then dividing by the number of response options on the test, minus 1.

Briefly describe the difference between norm referenced in criterion referenced tests.

Norm referenced tests involve comparing individuals to the normative group. With criterion referenced tests test-takers are evaluated as to whether they meet a set standard (e.g. a driving exam).

Briefly describe the two most common methods for measuring correlation.

Pearson r: A method of computing correlation when both variables are linearly related and continuous. Once a correlation coefficient is obtained, it needs to be checked for statistical significance (typically a probability level below .05). Spearman Rho: A method for computing correlation, used primarily when sample sizes are small or the variables are ordinal in nature.

Briefly describe the major assumptions regarding psychological based testing and assessment.

Psychological traits and states exist; traits are relatively stable; traits and states can be quantified and measured; test-related behavior predicts non-test-related behavior; tests have strengths and weaknesses; various sources of error are part of assessment; testing and assessment can be conducted in a fair manner; testing and assessment benefit society.

Briefly define standard error of measurement and how It is related to a confidence interval.

Standard error of measurement, often abbreviated as SEM, provides a measure of the precision of an observed test score. An estimate of the amount of error inherent in an observed score or measurement.; generally, the higher the reliability of the test , the lower the standard error; standard error can be used to estimate the extent to which an observed score deviates from a true score; confidence interval: a range or band of test scores that is likely to contain the true score.

Briefly define the term informed consent and discuss the various components of competency as it is related to informed consent.

Test-takers have a right to know why they are being evaluated, how the test data will be used, and what (if any) information will be released to whom. With full knowledge of such information, test-takers give their informed consent. Some groups (e.g. people with Alzheimer's Disease) may not have the capacity, or competency, to provide informed consent. Competency may be defined as: being able to evidence a choice as to whether one wants to participate; demonstrating a factual understanding of the issues; being able to reason about the facts of a study, treatment, or whatever it is to which consent is sought, and appreciating the nature of the situation. If competency, cannot be provided by the person, a substitute decision-maker is used (e.g. next of kin).

Define and compare the terms psychological assessment and psychological testing.

Testing is the process of measuring psychology-related variables by means of devices or procedures designed to obtain a sample of behavior; the objective is to obtain some gauge with regard to ability or attribute. Assessment is the gathering and integration of psychology-related data for the purpose of making a psychological evaluation through tools such as tests, interviews, case studies, behavioral observation, and other methods; the objective is to answer a referral question, solve a problem or arrive at a decision through the tools of evaluation. * The test is a tool of the assessment.

Briefly define the normal curve. Discuss the area under the normal curve as it relates to standard deviation.

The normal curve is a bell-shaped, smooth, mathematically defined curve that is highest at its center; it is perfectly symmetrical. Area under the normal curve: the normal curve can be conveniently divided into areas defined by units of standard deviations.

Compare and contrast z scores, T scores, and stanine scores.

They are all standard scores: raw scores that have been converted from one scale to another scale, where the latter scale has some arbitrarily set mean and standard deviation. Z-score - conversion of a raw score into a number indicating how many standard deviation units the raw score is below or above the mean of the distribution T scores - can be called a fifty plus or minus ten scale; that is, a scale with a mean set at 50 and a standard deviation set at 10 Stanine - a standard score with a mean of 5 and a standard deviation of approximately 2. Divided into nine units.

Briefly describe the ways in which psychologists have traditionally conceptualized validity.

Validity is often conceptualized according to three categories: 1. Content validity. This is a measure of validity based on an evaluation of the subjects, topics, or content covered by the items in the test. 2. Criterion-related validity. This is a measure of validity obtained by evaluating the relationship of scores obtained on the test to scores on other tests or measures 3. Construct validity. This is a measure of validity that is arrived at by executing a comprehensive analysis of a. how scores on the test relate to other test scores and measures, and b. how scores on the test can be understood within some theoretical framework for understanding the construct that the test was designed to measure