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Statistics Chapter 2
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Gravity
Terms in this set (35)
categorical data
individuals observations are categorical responses (nonnumerical)
Numerical dara
individual observations are numerical in nature
discrete numerical data
possible values are isolated points along the number line
continuous numerical data
possible values form an entire interval along the number line
bivariate data
each observations consists of two responses or values
multivariate data
each observation consists of two or more responses or values
observational study
a study that observes characteristics of an existing population
simple random sample of size n
a sample selected in a way that gives every different sample of size n an equal chance of being selected
stratified sampling
dividing a population into subgroups (strata) and then taking a separate random sample from each stratum
confounding variable
a variable that is related both to group membership and to the response variable
measurement or response bias
tendency for a sample to differ from the population because the method of observation tends to produce values that differ from the true value
selection bias
the tendency for a sample to differ from the population due to systematic exclusion of some part of the population
nonresponse bias
the tendency for a sample to differ from the population because measurements are not obtained from all individuals selected for inclusion in the sample
experiment
a procedure for investigating the effect of an experimental condition on a response variable
experimental condition
which is manipulated by the experiment
extraneous factor
a variable that is not of interest in the current study but it thought to affect the response variable
direct control
holding extraneous factors constant so that their effects are not confounded with those of the experimental condition
blocking
using extraneous factors to create experimental groups that are similar with respect to those factors, thereby filtering out the effect
randomization
random assignment to experimental conditions
replication
ensuring that there is an adequate number of observations on each experimental treatment
placebo treatment
a treatment that resembles the other treatments in an experiment, but which has no active ingredients
control group
a group that receives no treatment or a placebo treatment
increasing the size of the sample, although possibly desirable does nothing to reduce...
bias
methods for a simple random sample
-using slips of paper
-Sampling frame
-stratified sampling
sampling frame
a list of the objects/ individuals of a population using random number generator
the type of analysis that is appropriate and the conclusions that can be drawn from it are dependent own how ....
the data is collected
it would be __________ to study the entire population
FOOLISH
types of bias
selection bias, measurement/response bias, nonresponse bias
two methods of data collection
sampling, experimentation
variable
any characteristic whose value may change from one individual to another
examples of types of variables
calculator brand, # of books purchased, distance to the university
a univariate data set can be either:
categorical, numerical
multivariate data set would result from determining: (give some examples)
height, weight, pulse rate
discrete
usually arises when each observation is determined by counting (whole numbers)
continuous
no whole numbers, continuous numbers (27.23456)
;