BTW. ẍ is the same as x bar (symbol for a sample mean) but i cant do that on the computer.
Terms : Hide Images
| 156840901 | Alternative hypothesis | the theory that the researcher hopes to confirm by rejecting the null hypothesis. | |
| 156840902 | Association | when some of the variability in one variable can be accounted for by the other | |
| 156840903 | Bar graph | graph in which the frequencies of categories are displayed with bars; analogous to a histogram for numerical data | |
| 156840904 | Bimodal | distribution with two (or more) most common values; also called mode | |
| 156840905 | Binomial distribution | probability distribution for a random variable X in a binomial setting; P(X=x) = (n/x)(p)^x(1-p)^(n-x), where n is the number of independent trials, P is the probability of success on each trial, and x is the count of successes out of n trials. | |
| 156840906 | Binomial setting (experiment) | when each of a fixed number, n, of observations either succeeds or fails, independently, with probability p. | |
| 156840907 | Bivariate data | having to do with two variables | |
| 156840908 | Block | a grouping of experimental units thought to be related to the response to the treatment | |
| 156840909 | Block design (Blocking) | procedure by which experimental units are put into homogeneous groups in an attempt to control for the effects of the group on the response. | |
| 156840910 | Boxplot (box and whisker plot) | graphical representation of the 5-number summary of a data set. Each value in the 5-number summary is located over its corresponding value on a number line. A box is drawn that ranges from Q1 to Q3 and "whiskers" extend to the maximum and minimum values from Q1 and Q3 | |
| 156840911 | Categorical Data (Qualitative Data) | data whose values range over categories rather than values. | |
| 156840912 | Census | attempt to contact every member of a population. | |
| 156840913 | Center | the "middle" of a distribution; either the mean or the median | |
| 156840914 | Central limit theorem | theorem that states that the sampling distributions of a sample mean becomes approximately normal when the sample size is large. | |
| 156840915 | Chi-squared (X2) Goodness-of-Fit Test | compares a set of observed categorical values to a set of expected values under a set of hypothesized proportions for the categories; X2= ∑( (O-E)2/E) | |
| 156840916 | Coefficient of determination (r2) | set of all outcomes in the sample space that are not in the event. | |
| 156840917 | Complement of an event | set of all outcomes in the sample space that are not in the event. | |
| 156840918 | Completely randomized design | when all subjects (or experimental units) are randomly assigned to treatments in an experiment | |
| 156840919 | Conditional probability | the probability of one event succeeding given that some other event has already occurred | |
| 156840920 | Confidence interval | an interval that, with a given level of confidence, is likely to contain a population value; (estimate) ± (margin of error) | |
| 156840921 | Confidence Level | the probability that the procedure used to construct an interval will generate an interval that does contain the population value | |
| 156840922 | Confounding variable | has an effect on the outcomes of the study but whose effects cannot be separated from those of the treatment variable. | |
| 156840923 | Contingency Table (Two-way Table) | table that lists the outcomes of two categorical variables; the values of one category are given as the row variable, and the values of the other category are given as the column variable | |
| 156840924 | Continuous data | data that can be measured, or take on values in an interval; the set of possible values cannot be counted | |
| 156840925 | Continuous random variable | a random variable whose values are continuous data; takes all values in an interval | |
| 156840926 | Control (statistical control) | holding constant variables in an experiment that might effect the response but are not one of the treatment variables. | |
| 156840927 | Convenience sample | sample chosen without any random mechanism; chooses individuals based on ease of selection | |
| 156840928 | Correlation coefficient (r) | measures the strength of the linear relationship between two quantitative variables; r= 1/(n-1) ∑((xi-ẍ)/sx)((yi-ȳ)/sy) | |
| 156840929 | Correlation is not causation | just because two variables correlate strongly does not mean that one caused the other | |
| 156840930 | Critical value | values in a distribution that identify certain specified areas of the distribution | |
| 156840931 | Degrees of freedom | number of independent data points in a distribution | |
| 156840932 | Density function | a function that is everywhere non-negative and has a total area equal to 1 underneath it and above the horizontal axis | |
| 156840933 | Descriptive statistics | process of examining data analytically and graphically | |
| 156840934 | Dimension | size of a two way table; r x c | |
| 156840935 | Discrete data | data that can be counted (possibly infinite) or placed in order | |
| 156840936 | Discrete random variable | random variable whose values are discrete data | |
| 156840937 | Dotplot | graph in which data values are identified as dots placed above their corresponding values on a number line | |
| 156840938 | Double blind | experimental design in which neither the subjects nor the study administrators know treatment a subject has received | |
| 156840939 | Empirical Rule (68-95-99.7 Rule) | states that, in a normal distribution, about 68% of the terms are within one standard deviation of the mean, about 95% are within two standard deviations, and about 99.7% are within three standard deviations | |
| 156840940 | Estimate | sample value used to approximate a value of a parameter | |
| 156840941 | Event | in probability, a subset of a sample space; a set of one or more simple outcomes | |
| 156840942 | Expected value | mean value of a discrete random variable | |
| 156840943 | Experiment | study in which a researcher measures the responses to a treatment variable, or variables, imposed and controlled by the researcher. | |
| 156840944 | Experimental units | individuals on which experiments are conducted | |
| 156840945 | Explanatory variable (treatment/independent variable) | explains changes in response variable | |
| 156840946 | Extrapolation | predictions about the value of a variable based on the value of another variable outside the range of measured values | |
| 156840947 | First quartile | 25th percentile | |
| 156840948 | Five number summary | for a data set, [minimum value, Q1, median, Q3, maximum value] | |
| 156840949 | Geometric setting | independent observations, each of which succeeds or fails with the same probability, p; number of trials needed until first success is variable of interest | |
| 156840950 | Histogram | graph in which the frequencies of numerical data are displayed with bars; analogous to a bar graph for categorical data | |
| 156840951 | Homogeneity of proportions | chi-square hypothesis in which proportions of a categorical variable are tested for homogeneity across two or more populations | |
| 156840952 | Independent events | knowing one even occurs does not change the probability that the other occurs; P(A) = P(A/B) | |
| 156840953 | Inferential statistics | use of sample data to make inferences about populations | |
| 156840954 | Influential observation | observation, usually in the x direction, whose removal would have a marked impact on the slope of the regression line | |
| 156840955 | Interpolation | predictions about the value of a variable based on the value of another variable within the range of measured values | |
| 156840956 | Interquartile range | value of the third quartile minus the value of the first quartile; contains middle 50% of the data | |
| 156840957 | Least-squares regression line (line of best fit) | of all possible lines, the line that minimizes the sum of squared errors (residuals) from the line | |
| 156840958 | Lurking variable | one that has an effect on the outcomes of the study but whose influence was not part of the investigation | |
| 156840959 | Margin of error | measure of uncertainty in the estimate of a parameter; (critical value) x (standard error) | |
| 156840960 | Marginal totals | row and column totals in a two way table | |
| 156840961 | Matched pairs | experimental units paired by a researcher based on some common characteristic. | |
| 156840962 | Matched pairs design | experimental design that utilizes each pair as a block; one unit receives one treatment, and the other unit receives the other treatment | |
| 156840963 | Mean | sum of all the values in a data set divided by the number of values | |
| 156840964 | Median | halfway through an ordered data set, below and above which there lie an equal number of data values; 50th percentile | |
| 156840965 | Mode | most common value in a distribution | |
| 156840966 | Mound-shaped (bell-shaped) | distribution in which data values tend to cluster about the center of the distribution; characteristic of a normal distribution | |
| 156840967 | Mutually exclusive events | events that cannot occur simultaneously; if one occurs, the other doesn't | |
| 156840968 | Negatively associated | larger values of one variable are associated with smaller values of the other | |
| 156840969 | Nonresponse bias | occurs when subjects selected for a sample do not respond | |
| 156840970 | Normal curve | familiar bell-shaped density curve; symmetric about its mean; defined in terms of its mean and standard deviation | |
| 156840971 | Normal distribution | distribution of a random variable X so that P(a| | |
| 156840972 | Null hypothesis | hypothesis being tested~usually a statement that there is no effect or difference between treatments; what a researcher wants to disprove to support their alternative | |
| 156840973 | Observational study | when variables of interest are observed and measured but no treatment is imposed in an attempt to influence the response | |
| 156840974 | Observed values | counts of outcomes in an experiment or study; compared with expected values in a chi-square analysis | |
| 156840975 | One-sided alternative | alternative hypothesis that varies from the null in only one direction | |
| 156840976 | One-sided test | used when an alternative hypothesis states that the true value is less than or greater than the hypothesized value | |
| 156840977 | Outcome | simple events in a probability experiment | |
| 156840978 | Outlier | a data value that is far removed from the general pattern of the data | |
| 156840979 | P(A and B) | probability that BOTH A and B occur; P(A) x P(A/B) | |
| 156840980 | P(A or B) | probability that EITHER A or B occurs; P(A) + P(B) - P(A and B) | |
| 156840981 | Parameter | measure that describes a population | |
| 156840982 | Percentile rank | proportion of terms in the distributions less than the value being considered | |
| 156840983 | Placebo | an inactive procedure or treatment | |
| 156840984 | Placebo effect | effect, often positive, attributable to the patient's expectations that the treatment will have an effect | |
| 156840986 | Point estimate | value based on sample data that represents a likely value for a population parameter | |
| 156840988 | Positively associated | larger values of one variable are associated with larger values of the other | |
| 156840990 | Power of the test | probability of rejecting a null hypothesis against a specific alternative | |
| 156840993 | Probability distribution | identification of the outcomes of a random variable together with the probabilities associated with those outcomes | |
| 156840995 | Probability histogram | histogram for a probability distribution; horizontal axis are the outcomes, vertical axis are the probabilities of those outcomes | |
| 156840997 | Probability of an event | relative frequency of the number of ways an event can succeed to the total number of ways it can succeed or fail | |
| 156840998 | Probability sample | sampling technique that uses a random mechanism to select the members of the sample | |
| 156840999 | Proportion | ratio of the count of a particular outcome to the total number of outcomes | |
| 156841000 | P value | probability of getting a sample value at least as extreme as obtained by chance alone assuming the null hypothesis is true | |
| 156841001 | Quartiles | 25th, 50th, and 75th percentiles of a data set | |
| 156841002 | Random phenomenon | unclear how any one trial will turn out, but there is a regular distribution of outcomes in a large number of trials | |
| 156841003 | Random sample | sample in which each member of the sample is chosen by chance and each member of the population has a known, but perhaps unequal, chance to be in the sample | |
| 156841004 | Random variable | numerical outcome of a random phenomenon (random experiment) | |
| 156841005 | Randomization | random assignment of experimental units to treatments | |
| 156841006 | Range | difference between maximum and minimum values of a data set | |
| 156841007 | Replication | repetition of each treatment enough times to help control for chance variation | |
| 156841008 | Representative sample | sample that possesses the essential characteristics of the population from which it was taken | |
| 156841009 | Residual | in a regression, the actual value minus the predicted value | |
| 156841010 | Resistant statistic | one whose numerical value is not influenced by extreme values in the data set | |
| 156841011 | Response bias | bias that stems from respondents inaccurate or untruthful response | |
| 156841012 | Response variable | measures the outcome of a study | |
| 156841013 | Robust | when a procedure may still be useful even if the conditions needed to justify it are not completely satisfied | |
| 156841014 | Robust procedure | procedure that still works reasonably well even if the assumptions needed for it are violated; the t procedures are robust against the assumption of normality as long as there are no outliers or severe skewness | |
| 156841015 | Sample space | set of all possible mutually exclusive outcomes of a probability experiment | |
| 156841016 | Sample survey | using a sample from a population to obtain responses to questions from individuals | |
| 156841017 | Sampling distribution of a statistic | distribution of all possible values of a statistic for samples of a given size | |
| 156841018 | Sampling frame | list of experimental units from which the sample is selected | |
| 156841019 | Scatterplot | graphical representation of a set of ordered pairs; horizontal axis is first element in the pair, vertical axis is the second | |
| 156841020 | Shape | geometric descriptions of a data set: mound-shaped; symmetric, uniform; skewed; etc | |
| 156841021 | Significance level (α) | probability value that, when compared to the P value, determines whether a finding is statistically significant | |
| 156841022 | Simple random sample (SRS) | sample in which all possible samples of the same size are equally likely to be the sample chosen | |
| 156841023 | Simulation | random imitation of a probabilistic situation | |
| 156841024 | Skewed | distribution that is asymmetrical | |
| 156841025 | Spread | variability of a distribution | |
| 156841026 | Skewed left (right) | asymmetrical with more of the tail on the left (right) than on the right (left) | |
| 156841027 | Standard deviation | square root of the variance, s= √ (∑ (x-ẍ)^2/ (n-1) ) | |
| 156841028 | Standard error | estimate of population standard deviation based on sample data | |
| 156841029 | Standard normal distribution | normal distribution with a mean of 0 and a standard deviation of 1 | |
| 156841030 | Standard normal probability | normal probability calculated from the standard normal distribution | |
| 156841031 | Statistic | measure that describes a sample (e.g. Sample mean) | |
| 156841032 | Statistically significant | a finding that is unlikely to have occurred by chance | |
| 156841033 | Statistics | science of data | |
| 156841034 | Stemplot (stem and leaf plot) | graph in which ordinal data are broken into "stems" and "leaves"; visually similar to a histogram except that all the data are retained | |
| 156841035 | Stratified random sample | groups of interest (strata) chosen in such a way that they appear in approximately the same proportions in the sample as in the population | |
| 156841036 | Subjects | human experimental units | |
| 156841037 | Survey | obtaining responses to questions from individuals | |
| 156841038 | Systematic bias (unbiased estimate) | the mean of the sampling distribution of a statistic does not equal the mean of the population | |
| 156841039 | Systematic sample | probability sample in which one of the first n subjects is chosen at random for the sample and then each nth person after that is chosen for the sample. | |
| 156841040 | T distribution | the distribution with n-1 degrees of freedom for the t statistic | |
| 156841041 | T statistic | t= (ẍ-μ)/ (s/√n) | |
| 156841042 | Test statistic | (estimator - hypothesized value)/ standard error | |
| 156841043 | Third quartile | 75th percentile | |
| 156841044 | Tree diagram | graphical technique for showing all possible outcomes in a probability experiment | |
| 156841045 | Two sided alternative | alternative hypothesis that can vary from the null in either direction; values much greater than or much less than the null provide evidence against the null. | |
| 156841046 | Two sided test | a hypothesis test with a two sided alternative | |
| 156841047 | Type 1 error | the error made when a true hypothesis is rejected | |
| 156841048 | Type 2 error | the error made when a false hypothesis is not rejected | |
| 156841049 | Undercoverage | some groups in a population are not included in a sample from that population | |
| 156841050 | Uniform | distribution in which all data values have the same frequency of occurrence | |
| 156841051 | Univariate data | having to do with a single variable | |
| 156841052 | Variance | average of the squared deviations from their mean of a set of observations; s^2= (∑ (x-ẍ)^2)/ (n-1) | |
| 156841053 | Voluntary response bias | bias inherent when people choose to respond to a survey or poll; bias is typically toward opinions of those who feel most strongly. | |
| 156841054 | Voluntary response sample | sample in which participants are free to respond or not to a survey or a poll | |
| 156841055 | Wording bias | creation of response bias attributable in the phrasing of a question | |
| 156841056 | Z score | number of standard deviations a term is above or below the mean; z=(ẍ-μ)/ (s/√n) or z= (ẍ-μ)/ (σ/√n) |
