The key difference between projective and objective personality tests is the way they are scored. Objective tests, which often involve self-report methods and “true/false” or multiple choice questions, are scored in a standardized, predetermined way. For example, if Joe and Anne both bubble in the exact same set of answers for a certain personality test, their score reports will show the exact same results. Contrastingly, projective tests generally don’t use a hard-coded method of scoring participant responses. Instead, the psychologist interprets a freeform response to an ambiguous stimulus and attempts to infer meaning from it, sometimes using guides created for this task as a reference. Both the Thematic Apperception Test (TAT) and the Rorschach Inkblot Test are projective tests. The TAT uses ambiguous, uncaptioned scenes as the ambiguous stimuli, while the Rorschach uses monotone, symmetrical inkblot splatters as the ambiguous stimuli.

Naturalistic observation refers to watching individuals in their “natural habitat” when laboratory observation would be cost-prohibitive, impossible, or otherwise unrealistic. The defining feature of naturalistic observation is watching individuals and recording data about their behaviors in the normal, unaltered environment. This can be useful when the individuals might change their behavior when they are aware they’re being watched (i.e. a phenomenon sometimes called the Hawthorne effect). The example involving sitting at a park is naturalistic observation, because the researcher is observing the behavior of parents of children at play in their natural environment, as opposed to bringing the parent-children pairs into a lab and then observing the parents’ behavior. The other examples all involve bringing human subjects into a lab setting, which by definition is not naturalistic observation.

The correct answer is "electroencephalography (EEG)." In EEG, the researcher applies electrodes to the participant’s (or patient’s) scalp and records the electrical signals emitted by the brain. Recall that neurons communicate with one another using electrical impulses. The electrodes are placed in specific places that allow the researcher to measure activity in different areas of the brain. This technique is often used in sleep research.

Double blind studies collect experimental data to draw conclusions, not correlational data! In other words, researchers are able to examine cause and effect relationships due to the random assignment of participants to a control group or an experimental group.

A Pearson correlation between two variables indicates that as one variable increases, another variable either increases or decreases by some amount in a linear manner.

Correlations range between  and , with  signifying the strongest possible negative correlation between two variables,  signifying the strongest possible positive correlation, and  signifying the complete absence of any correlation between two variables.

An illusory correlation occurs when someone thinks that two variables are related, but they are actually not (they have a correlation of 0). 

Correlation coefficients range from -1 to 1, with the strongest correlations being closer to -1 or 1. A correlation of 0 indicates no relationship between two variables. Negative correlations can be as strong or stronger than positive correlations; the most important factor is the magnitude of the correlation.

The median is the middle number in a data set. For example, the median of {3, 7, 4, 5, 8} is 5. The terms must first be placed in increasing order: {3, 4, 5, 7, 8}. From here, it becomes evident that 5 is the middle term, or median.

Statistics play a big role in much of the research in the field of psychology. In studying groups of people and individuals, their behaviors, reactions, etc. a researcher will have lots of numerical data on their hands. Statistics is the analysis of this numerical data.