**T-Score**

A standard score that sets the mean to fifty and standard deviation to ten. Used on a number of tests including the MMPI.

**t-Test**

A group of statistics used to determine if a significance difference exists between the means of two sets of data.

**Tactile**

The sense of touch.

**TAT**

See Thematic Apperception Test

**Temperament**

A person’s typical way of responding to his or her environment.

**Temporal Lobe**

One of the four lobes of the brain. Contains the auditory cortex and therefore plays a role in receptive language as well as memory and emotion.

**Test-Retest Reliability**

The correlation coefficient determined by comparing the scores of the same measuring device administered to the same people on two different occasions.

**Tetrachoric Correlation**

A correlational technique used to estimate the Pearson-Product correlation of two continuous variables that have been dichotomized (Example: age is continuous, but when it is split into two groups, such as over 40 and under 40, it becomes dichotomous).

**Thalamus**

Considered the central switching station of the brain because all of the body’s senses (except the olfactory senses) pass through this before being relayed to the brain.

**Thematic Apperception Test (TAT)**

A subjective personality test where ambiguous pictures are shown to a subject and they are asked to tell a story related to them.

**Theory**

A general idea about the relationship of two or more variables.

**Time Series Design**

A research design where subjects are measured at specific times before and after the treatment has been administered in order to determine the long term effects of the treatment

**Trait**

A relatively permanent internal characteristic (e.g., friendly, outgoing)

**Transference**

Intense feelings directed toward the therapist that many clients experience in the process of therapy.

**Trial and Error Learning**

Learning that takes place through the application of possible solutions to a problem.

**True Experiment**

Research design that utilizes the most control over subjects and utilizes randomization

**True Score**

the amount of the observed score that truly represents what you are intending to measure.

**Two-Way ANOVA**

An Analysis of Variance used when there are two independent variables.

**Type A Personality**

A theory used to describe a person with a significant number of traits focused on urgency, impatience, success, and excessive competition.

**Type B Personality**

A theory used to describe person with a significant number of traits focused on relaxation, lack of urgency, and normal or reduced competition.

**Type I Error**

The error that is committed when a true null hypothesis is rejected erroneously. The probability of a Type I Error is abbreviated with the lowercase Greek letter alpha.

**Type II Error**

The error that is committed when a false null hypothesis is accepted erroneously. The probability of a Type II Error is abbreviated with the uppercase Greek letter beta

*Source: Allpsych Online*