# Statisical Methods Appendix A.txt

 Statistics The branch of applied mathematics that researchers use to organize, describe, and draw conclusions about the quantitative results of their studies Descriptive statistics Statistics used to organize, summarize, and describe dataIncludes measures of central tendency, variability, and relationships Measures of central tendency a measure or score that describes the center, or middle, of a distribution or scoresMean � the arithmetic average of a group of scoresMedian � the middle score or value when scores are arranged from highest to lowestMode � the score that occurs most frequently in a group of scores Histogram A bar graph that depicts the number of scores within each class interval in a frequency distribution Variability How much the scores in a distribution spread out away from the mean Range The difference between the highest score and the lowest score in a distribution of scores Standard deviation A descriptive statistic reflecting the average amount that scores in a distribution deviate, or vary, from their mean Normal curve A symmetrical bell-shaped frequency distribution that represents how scores are normally distributed in a populationMost scores fall near the mean, and fewer and fewer scores occur in the extremes above or below the mean68% of scores in a normal distribution fall within 1 standard deviation of the mean (34.13% above and 34.13% below)Almost 95.5% of scores deviations above and99.72% fall between above and below The Correlation Coefficient A numerical value indicating the strength and direction of a relationship between two variable Positive correlation A relationship between two variable in which both vary in the same direction Negative correlation A relationship between two variable in which an increase in one variable is associated with a decrease in the other variable Inferential Statistics Statistical procedures based on probabilities that allow researchers to make inferences about the characteristics of the larger population from observations and measurements of a sampleEstimates are derived of how much confidence can be placed in those inferences Population The entire group of interest to researchers and to which they wish to generalize their findings; the group from which a sample is selected Sample The portion of any population that is selected for study and from which generalizations are made about the entire population Tests of statistical significance Statistical tests that estimate the probability that a particular research result could have occurred by chanceThe estimates derived from tests are stated as probabilitiesA probability of .05 means that the experimental results would be expected to occur by chance no more than 5 times out of 100The .05 level is usually required as a minimum for researchers to conclude their findings are statistically significant Replication The process of repeating a study with different participants and preferably a different investigator to verify research Authorkiki10 ID35296 Card SetStatisical Methods Appendix A.txt DescriptionStatisical Methods Appendix A Updated2010-09-17T03:30:33Z Show Answers