AP Exam

5 number summary : The minumum value, lower quartile, median, upper quartile, and maximum value for a data set. These five values give a summary of the shape of the distribution and are used to make box plots.The five numbers that help describe the center, spread and shape of data

z score : a measure of how many standard deviations you are away from the norm (average or mean)-Number of standard deviations a score is above or below the mean (positive above, negative below

bar graph : a type of graph in which the lengths of bars are used to represent and compare data in categoriesA graph that uses horizontal or vertical bars to represent data.

parameter : (n) a determining or characteristic element; a factor that shapes the total outcome; a limit, boundarya characteristic or constant factorsomething that determines the limits of certain data values

nonresponse : bias introduced to a sample when a large fraction of those sampled fails to respondWhen many people of a sample do not respond

voluntary response bias : Bias introduced to a sample when individuals can choose on their own whether to participate in the sample.

scatterplot : A graphed cluster of dots, each of which represents the values of two variables. The slope of the points suggests the direction of the relationship between the two variables. The amount of scatter suggests the strength of the correlation (little scatter indicates high correlation).

correlation : A measure of the extent to which two factors vary together, and thus of how well either factor predicts the other. The correlation coefficient is the mathematical expression of the relationship, ranging from -1 to +1

empirical rule : The rules gives the approximate % of observations w/in 1 standard deviation (68%), 2 standard deviations (95%) and 3 standard deviations (99.7%) of the mean when the histogram is well approx. by a normal curve

lurking variable : A variable that has an important effect on the relationship among the variables in a study but is not one of the explanatory variables studied

descriptive statistics : Mathematical procedures for organizing collections of data, such as determining the mean, the median, the range, the variance, and the correlation coefficient

mean : A measure of center in a set of numerical data, computed by adding the values in a list and then dividing by the number of values in the list.

Q1 : A location measure of the data such that has one fourth or 25% of the data is smaller than it. Found by dividing the ordered data set in half (excluding the middle observation if n is odd) and finding the median of the lower half of the data.

Q3 : A location to measeure when counting data to such as the median where instead of counting 50% it is 75% from the beginning of the sorted data

simple random sample : A sample selected in such a way that every element in the population or sampling frame has an equal probability of being chosen. Equivalently, all samples of size n have an equal chance of being selected.A sample of size n selected from the population in such a way that each possible sample of size n has an equal chance of being selected.

sampling distribution : Distribution of sample proportions from sample to sample. A sampling distribution of a sample statistic for a fixed sample size n is the distribution of that statistic derived from every possible sample of size n for a given population.A distribution of statistics obtained by selecting all the possible samples of a specific size from a population

Interpolation : The estimation of an unknown number between known numbers. Interpolation is a way of approximating price or yield using bond tables that do not give the net yield on every amount invested at every rate of interest and for every maturity.

Qualitative : Data in the form of recorded descriptions rather than numerical measurements.

double blind : An experiment in which neither the subjects nor the people who work with them know which treatment each subject is receivingNeither the subjects nor the people who have contact with them know which treatment a subject received

placebo : A fake treatment.A chemically inert substance that produces real medical benefits because the patient believes it will help her

matched pairs : an observational technique that involves matching each participant in the experimental group with a specific participant in the control group in order to eliminate the possibility that a third variable (and not the independent variable) caused changes in the dependent variable

conditional prabability : probability given that something else has already occurred

binomial : A two-name naming system.

unimodal : having one mode; this is a useful term for describing the shape of a histogram when it's generally mound-shapeda data set with one mode such a normal distribution usually has only one mode

snowball : Huyen wanted to conduct market research to find out why students were unhappy with Marketing 431, probably the finest course ever to be offered by a university. In order to do this she needed to find people who were unhappy with the course. Figuring that these people would talk to each other, she used a sampling technique where she found one person who was unhappy with the course and, after asking her research questions, asked this person for the name of another person who was unhappy with the course.

IQR : A measure of variability, based on dividing a data set into quartilesDifference between upper and lower quartile of a boxplot

simulation : A representation of a situation or problem with a similar but simpler model or a more easily manipulated model in order to determine experimental results.

degrees of freedom : The number of individual scores that can vary without changing the sample mean. Statistically written as 'N-1' where N represents the number of subjects.

discrete random variable : ...

central limit theorem : ...

z test : ...

t test : ...

contingency table : displays counts, and, sometimes, percentages of individuals falling into named categories on two or more variables. The table categorizes the individuals on all variables at once, to reveal possible patterns in one variable that may be contingent on the category of the other.A two-variable table with cross-tabulated data.

stem and leaf display : A multiple column table depicting the individual digits of the scores. A score of 95 would have a stem of 9 and a leaf of 5, a score of 62 would have a stem of 6 and a leaf of 2. If a particular stem has more than one leaf, such as the scores 54, 58, and 51, the stem of 5 has three leaves, in this case 458.. It shows the range of values of the variable

se : standard deviation of residuals

r-squared : overall measure of how successful the regression is in linearlly relating to y and x

pilot : small trial run of a survey to see if questions are clear

convenience sample : Choosing a sample because it is convenient.failing to get a proper representation of the population because If you survey everyone on your soccer team who attends tonight's practice, you are surveying a convenience sample.

statistic factor : A multifactor model in which statistical methods are applied ot a set of historical returns to determine portfolios that best explain either historical return covariances or variances.

control group : In an experiment, the group that is not exposed to the treatment; contrasts with the experimental group and serves as a comparison for evaluating the effect of the treatment.