289)Field research is descriptive or experimental research that is conduced in a natural setting outside the laboratory. 290)Double-blind studies are conducted in order to avoid the powerful influence of experimenter effects on the results of an experiment. 291)A disadvantage of the naturalistic observation is that it allows the researcher little or no control of the situation. 292)A disadvantage of correlational research is that it does not permit identification of cause and effect. 293)An advantage of the naturalistic observation is that it allows the use of sophisticated equipment. 294)An advantage of the laboratory observation is that it allows the use of sophisticated equipment. 295)The arithmetic mean is a commonly used measure of variability. 296)The arithmetic mean is an average that is calculated by adding up a set of quantities and dividing the sum by the total number of quantities in the set. 297)Descriptive statistics are statistical procedures that organize and summarize research data. 298)The standard deviation is a commonly used measure of variability that indicates the average difference between scores in a distribution and their mean.