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exam 2 terms
terms from outline
40
Internet/New Media
Undergraduate 2
10/10/2012

Additional Internet/New Media Flashcards

 


 

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Term
Nonprobability Sample
Definition
a sample in which the items have unknown
probabilities of being selected.
Example: Convenience Sample and judgement sampling
Term
Probability Sample
Definition
sample
in which items are selected based upon known probabilities.
Example: Simple Random Sample, systematic, stratified, and cluster
Term
making
conclusions about the population,
that is, for statistical inference.
Definition
****Probability sampling is
NECESSARY when
Term
Sampling Error
Definition
the error
incurred by taking a sample
instead of a census. (Remember
as soon as you look at anything
less than the entire population,
you are not going to report with
100% accuracy the
characteristics of the population).
Term
Nonsampling Error
Definition
(referred to
as Bias) – error that results in a
distortion of conclusions.
Term
Nonresponse Error
Definition
error
incurred when some subjects
refuse to respond to a survey

Example: Estimating percentage of car crashes that
involve alcohol. Drunk drivers usually refuse the
BAC test.
Term
Coverage Error
Definition
occurs when certain items are
excluded from the sampling
frame.
Term
Measurement Error
Definition
when data collected do not reflect
the true measures.

Example: CDC Hepatitis Survey, Teacher Evaluation
requiring you to fill in your
name, order of survey
questions, etc.
Term
To make conclusions
about the population based upon
a single sample.
Definition
Major Goal of inferential
statistics:
Term
Political Pollsters
Definition
The
sample proportion is used to
estimate the actual proportion of
the votes that each candidate will
get from the population of voters
(i.e: those people who actually get
out and vote).
Term
sample mean
Definition
( ) as a random
variable itself.Definition: The set of all possible
sample statistics ( ’s) could be
represented by a histogram, or
distribution. This distribution is
referred to as a sampling distribution.
Term
mean and standard
deviation.
Definition
The sampling distribution has its
own
Term
sampling distribution of the mean.
Definition
The distribution of all possible
sample means is called the
Term
Central Limit Theorem:
Definition
If the population is not normal (or unknown), then the shape of the sampling distribution is normal for large samples (n≥30).
Term
point estimate
Definition
consists of a single sample statistic used to estimate the true value of the population parameter (either µ or π).
Term
the
parameter of interest is the
population proportion of successes, π.
Definition
Remember
that for categorical variables
Term
convenience sampling
Definition
items are selected based only on the fact that they are easy, inexpensive, or convenient to sample.
Term
judgment sample
Definition
you get the opinions of pre-selected experts in the subject matter
Term
Simple random sample and Systematic sample
Definition
Simple to use
May not be a good representation of the population’s underlying characteristics
Term
Stratified sample
Definition
Ensures representation of individuals across the entire population
Term
Cluster sample
Definition
More cost effective
Less efficient (need larger sample to acquire the same level of precision)
Term
Coverage error SW
Definition
appropriate frame?
Term
Nonresponse error SW
Definition
follow up
Term
Measurement error SW
Definition
good questions elicit good responses
Term
Sampling error SW
Definition
always exists
Term
Coverage error or selection bias SE
Definition
Exists if some groups are excluded from the frame and have no chance of being selected
Term
Non response error or bias SE
Definition
People who do not respond may be different from those who do respond
Term
Sampling error SE
Definition
Variation from sample to sample will always exist
Term
Measurement error SE
Definition
Due to weaknesses in question design, respondent error, and interviewer’s effects on the respondent (“Hawthorne effect”)
Term
Standard Error of the Mean

Note that the standard error of the mean decreases as the sample size increases
Definition
A measure of the variability in the mean from sample to sample is given by the
Term
n
Definition
sample size
Term
central limit theorem
Definition
As the sample size gets large enoughthe sampling distribution of the sample mean becomes almost normal regardless of shape of population
Term
point estimate
Definition
single number, the sample statistic estimating the population parameter of interest
Term
confidence interval
Definition
provides additional information about the variability of the estimate
Term
interval estimate
Definition
provides more information about a population characteristic than does a point estimate
Term
Point Estimate ± (Critical Value)(Standard Error)
Definition
The general formula for all confidence intervals is:
Term
standard error
Definition
is the standard deviation of the point estimate
Term
substitute the sample standard deviation, S
Definition
If the population standard deviation σ is unknown, we can
Term
adding an allowance for uncertainty to the sample proportion ( p )
Definition
An interval estimate for the population proportion ( π ) can be calculated by
Term
Sampling is less time consuming and less costly
Sampling provides an objective way to calculate the sample size in advance
Sampling provides results that are objective and defensible.
Because the sample size is based on demonstrable statistical principles, the audit is defensible before one’s superiors and in a court of law

Sampling provides an estimate of the sampling error
Allows auditors to generalize their findings to the population with a known sampling error.
Can provide more accurate conclusions about the population
Sampling is often more accurate for drawing conclusions about large populations.
Examining every item in a large population is subject to significant non-sampling error
Sampling allows auditors to combine, and then evaluate collectively, samples collected by different individuals.
Definition
Six advantages of statistical sampling in auditing
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