# PT 1.2.1

 inferences logical deductions about events that cant be observed directly what are descriptive stats? methods used to provide a concise descroption of a collection of quantitative information inferential statistics methods used to make inferences from a small group of people (sample), to a large group of people (population) What type of stats is psych testing based on? inferential stats what is measurement? application of rules for assigning numbers to objects What are 3 things that scales can have? -magnitude -equal intervals -absolute 0 (things scales can have) Magnitude moreness*taller or shorter (things scales can have) Equal intervals the difference between two points next to each other is the same*such as inches (things scales can have) absolute 0 it is possible to have none of a particular quality being measured*heart rate of a person is 0, nothing 4 types of scales -nominal - ordinal -interval - ratio (types of scales) nominal -not really scales just assigning random designator number to people or things*either yes or no (types of scales) Ordinal scales has the property of moreness but not equal intervals or absolute 0 (types of scales) interval scales has magnitude and equal intervals but not necessarily the absolute 0*temp in F or C (types of scales) ratio scales has magnitude, equal intervals, and absolute *focus more on this one For each observation in a nominal data, how mmany categories can it go to? one*it cannot be used for mathematical manipulations but can be used for frequency dist. Can ordinal data be manipulated and difficult to interpret it can be manipulated and difficult to interpret Can we make statements about ratios with interval data? no frequency distirbution summarizes the scores of a group of individuals in terms of how frequently each value is obtained What does a bell-shaped curve distribution mean? mean, median, and mode are at the same spot positive skew meaning? more scores are above the mode than below it negative skew meaning? more scores are below the mode than above it class interval is the distance between 2 consecutive measurements*one decides the meaningful difference between one measurement and the next one*temp, money, length percentile is a measure of what? relative performance*population hsould be specified standard deviation an approximation of the average deviation around the mean variance variation of the scores around the mean calculated as squared deviation around the mean which is more meaningful, SD or vairnace? SD what does lower case sigma refer to? standard deviation of population what does the S stand for? standard deviation of a sample drawn from that population what does the z-score indicate? distance of a score from the mean in SD Whats a zscore of 1.0 mean in percentiles? the persons score is at ~84th percentile whats a zscore of -1.0 mean in percentile? ~16th percentile What is the SD of wechsler IQ tests? 15 bc that was the closest to the standford-binet which was 16 why are the wechsler IQ scores significant? they are based on population stats alone and no longer make use of calc. of mental age.*score tells us where the individual scores relative to their peers****CALLED DEVIATION IQ SCORE what is another name for standard normal distribution? symmetrical binomial probability distribution who developed a system in which the SD comes in equaling to 10? W.A McCall For McCalls T, what number is the mean? 50 rather than 0 whats formula of converting z score into t-score? T=10Z+50 how do quartile systems divide percentage scale? into 4ths how do deile systems divide percentage? tenths What are stanines? divided scores into 9ths making 3 groups of lower, middle, and upper. what do norms refer to? the performances by defined groups on particular tests*these are the scores a sample is compared to what do norm referenced tests do? compare individuals to a normative group*make somebody look bad helps you look better what do criterion referenced tests do? compare an individual to a crtierion on specific taks, skills, or knwoledge.*these are used mainly for diagnostic purposes***making somebody else look bad doesnt help you If there is a standardization sample, the test has ______ _____ normative data Authorefrain12 ID232699 Card SetPT 1.2.1 Descriptionchapter 2 Updated2013-09-14T02:07:12Z Show Answers