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biostats
test 1
104
Nursing
Graduate
06/04/2012

Additional Nursing Flashcards

 


 

Cards

Term
a set of inter-related constructs (concepts), definitions, propositions, that present a systematic view of phenomena by specifying relations among variables for the purposes of explaining and predicting phenomena
Definition
theory
Term
the ____ tests the theory
Definition
hypothesis
Term
this is the statement of the relationship between the independent and the dependant variables
Definition
hypothesis
Term
this is the investigator's hunch or expectation
Definition
research hypothesis
Term
another name for a guiding hypothesis
Definition
research hypothesis
Term
what is the  statement that allows verification by using a test?
Definition
statistical hypothesis
Term
null hypothesis (ho)
Definition
"there will be no statistically significant difference"
Term
the null hypothesis is based on the _____ of _____
Definition
laws of proof
Term
what is the laws of proof?
Definition
if one can falsify the null then the opposite or alternative must be accepted
Term
define directional hypothesis (hd)
Definition

there will be a statistically significant difference in

indicates where the difference will be found(ie the direction)

* not commonly used in research, except in epidemiology b/c assumed exposure to diseases or agents usually doesn't result in better health!

Term

this variable is the characteristic that the researcher controls or manipulates according to the purpose of the study

 

used to classify or categorize subjects or groups

Definition
independent variable
Term

a measure of the effect of the independent variable

used to measure outcomes or compare differences

may be measured before and after the conditions are manipulated

Definition
dependent variable
Term

these are variables that interfere in a study "bugs", must be eliminated(controlled)

characteristics not of primary interest that affect the dependent variable

Definition
intervening (confounding) variables
Term
name the four levels of measurement
Definition

Nominal

ordinal

ratio

interval

Term
examples of nominal levels of measurement and definition
Definition

mutually exclusive categories, but have no order or meaning

 

male, female,

 

No mathmatics**

Term
define ordinal levels of measurements
Definition

mutually exclusive categories based on some defined characteristics and the relative amt of that characteristic with a logical order to the categories

ex agree, disagree,

 

never use math on this level of data**

Term
which levels of data do you not use math on?
Definition

NO math on

 

Nominal

Ordinal

Term
discuss interval data
Definition

classifies objects into mutually exclusive categories based on defined characteristics

logical order

and equal units of differences

 

example= units

 

can use math

Term
ratio levels of measurement
Definition

mutually exclusive categories, based on some defined characteristic  and the relative amt. of that characteristic with a logical order, equal units of difference and a meaningful zero point, representing absence of the characteristic

example= # of cigarettes

WBC count

 

Term
2 types of categorical data
Definition
nominal and ordinal
Term
2 types of continuous measures
Definition
ratio and interval
Term
formula for observed measurement=
Definition
observed measurement= the true value + error
Term
can you use means, standard deviations for ordinal level data?
Definition
No
Term
are small or large sample sizes vulnerable?
Definition
small are more vulnerable
Term
chance variation is also called what?
Definition
error
Term
_____focuses on the consistency with which a measurement is taken?
Definition
Reliability
Term
discuss instrument reliability
Definition

focuses on the consistency of measurement by a particular instrument- what if the instrument is faulty?

the key with instrument reliability is calibration

Term
intra-rater reliability focuses on what?
Definition

consistency with which an individual takes measurements

is it done the same by the person every time?

poor technique?

consistenly following technique?

Term
inter-rater reliability focus on what?
Definition

consistency in measurements between or among more than 1 individuals taking the measurements.

must be an adequate assurances that changes are true rather than b/c of error-

*does everyone follow the same protocol for measuring?

Term
is the pearson correlation appropriate for measuring reliability? why or why not?
Definition
No, b/c it ignores systematic errors
Term
wwhat is the preferred measure for reliability for continuous data?
Definition
ICC-itra-class correlation coefficient
Term
the best ways to improve reliability are to do what?
Definition
follow a protocola and practice the protocol before taking measurements
Term
ICC ranges
Definition

0 to 1.00

0.9 or above -excellen reliability

.75-0.89 good to verygood

below 0.75 mod to poor

the lower the worse

Term
reasons for low ICC
Definition

1. rateres and ratings do not agree

2. lack of sufficient variability of subjects' scores(range)

 

Term
what does measuring validity mean?
Definition

does the test or measure actually do what it is intended to do?

are we measuring what we think we are measuring?

Term

what type of validity?

does the mesurement appear appropriate?

Definition
face validity
Term

what type of validity

is the measurement based on theory?

Definition
construct validity?
Term

waht type of validity

 

is the test broad enough to address the scope of the content?

(example: anatomy, only covers sm. part of the body, not the whole thing)

Definition
content validity
Term

what type of validity?

 

how does the test perform?

is it useful?

Definition
criterion validity
Term

what type of validity

 

does the test predict a specific phenomenon or outcome?

Definition
predictive validity
Term

what type of validity?

 

does the test perform as well as an accepted test?

does a smaller test do as good as a bigger, or the gold standard?

Definition
concurrent validity
Term

what type of validity?

does the test predict well enough to determine an intervention?

Definition
prescriptive validity
Term
what type of validity is concerned with limiting or controlling factors and events, other than the independent variable, which may cause changes in the outcome(dependent variable)
Definition
internal variable
Term
which type of validity is concerned with factors which may affect the generalization of the conclusions drawn from a study
Definition
external validity
Term
what are the three temporal threats to internal validity?
Definition

history, maturation, and attrition

history-passage of time,

maturation-age(developmental changes, like that of a toddler)

attrition-drop out, ex. if happy with treatment drop out of study, the only ones left are those who are not being helped

 

Term
what are the threats to measuring effects on internal validity
Definition

testing-the act of testing itself, once testing is done learning is done about test, can't repeat

instrumentation- what if there is a problem with instrument chosen to test (ex in class testing writing with "pencil-like object" but not really pencil, this learning affects handwriting also)

statistical regression to the mean-tendancy for outliers to move toward the mean as test is repeated, due to laws of probability

sampling-bias

 

Term
population effects to external variability
Definition

1. accessibility-the subject may not represent the entire population, which may include individuals wha have comprimised access to medical care and treatment

2.  subject treatment interaction-everybody reacts differently-we are all genetically different.

Term
ecological threats and concerns related to external validity
Definition

1. description of the variables-not given enough data to exactly replicate and get same results

2.  multiple treatments (test order)-potentiation of therapies-fatigue, physiology of test-what was done first

Term
this is an effect on test subjects knowing they are test subjects, they have better compliance than those not be tested-it is a threat to external validity
Definition

hawthorne effect

 

Term
discuss pre-test/post-test sensitization
Definition

individuals anticipate what will be tested, this is an external validity threat

 

Term
what is it called when a person's charissma or the person doing the study affects the outcome ?
Definition
Rosenthal effect-example of a threat to external validity
Term

R=

M=

O=

X=

Definition

R=randomized

M=subjects are matched

O= means measurement

X=treatment

 

Term

what type of design is

characterized by

  • no control group
  • sesitivity to temporal threats to internal validity
  • poor generalization
Definition
pre-experimental designs
Term

the investigator measures temp. of a sample of children on day before and one day after innoculation

 

plot and this is an example of what?

Definition

O   X   O 

 

pre-experimental design

"before-after"

no control grom is described

 

Term

what type of design

  • is the gold standard
  • randomized-likelihood is balanced
  • there is a control group-comparison
Definition

experimental designs

 

Term
randomization is used to help _____ factors among groups
Definition
balance
Term

randomization means what?

 

not?

Definition

randomization= equivilant

NOT=identical

Term

ex. women with RA were randomly assigned to one of 3 tx groups: heat, cold, contrast baths, edema was measured using an immersion technique one day before tx and later after they received 6 tx's (before tx and after tx measurements)

 

plot and describe design

Definition

this is a pretest-post test control group design using 3 groups. because pts are used a strict control (withholding tx) cannot be used

R  O X1 O

R  O X2 O

R  O X3 O

Term

ex. in order to compare the effects of tPA and no tPA , pts presenting within 4 hrs of a CVA were randomly selected to receiveor not receive tPA. 6 days after admission to hosp. pts. wree compared

 

do diagram and explain this test

Definition

R  XtPA  O

R XnotPA O

 

tis is experimental design, but no pretest is possible b/c cannot prediagnose CVA

Term

 do diagram and explain type of test

in order to test the effect of pos. imagery on psycomotor skills 2 classes form the same school were used.  the subjects in 1 class received instruction on visual imagery  while the other class did not.  Subjects' times to complete the psycomotor test battery were measured before and after one clase received visual imagery training

Definition

this is a quasi-experiment b/c 2 whole classes were compared and one does not know it is the equivalent

 

O  XO

-----------

O XO

Term
this type of design has characteristics of experimental design, but lacks at least 1 of the typical characteristics that would make them"true" experimental design.
Definition
quasi-experimental design
Term
all members defined on some specification
Definition
population
Term
a  subset of a population is a _____
Definition
sample
Term
a descriptor ex. avg age
Definition
parameter
Term

what type of sample?

 

any subject that qualifies is included

Definition
convenience
Term

what type of sample?

 

all potentioal subjects from a specific source

Definition
cluster
Term

all subjects are chosen form a protocol, for example, every fifth M and M

is what type of sample?

Definition
systematic
Term

this type of sample -subjects are chosen so that the composition lof the sample represents the population on specified characteristics

(ex. if asking nurses and 85% are female-make sure 85% of your sample is also female)

want it to look similar

Definition
stratified
Term
type of sampling-every potential subject has an equal likelihood of being included in the sample
Definition
random sampling
Term
black jack is what type of sampling?
Definition
random without replacement
Term

what type of sampling-after a subject is chosen at random, the subject is returned to the population, usually not used in clinical research

odds don't change-slot machine!

50 in 1 is same as 1 in 50

Definition
random sampling with replacement
Term

what type of sampling- after a subject is chose at random the subject is not returned to the population

this method is typically used in clinical researc

Definition
random sampling without replacement
Term
what is the probability?
Definition
it's the proportion of outcomes that meet a criterion divided into all possible outcomes
Term
probability of having a girl
Definition

p= girl/boy, girl

1/2=50%

 

Term

replacement vs not

drawing the king of hearts in 2 draws

replacement 1/52 AND 1/52

no replacement 1/52 and 1/51

 

Definition
Term
what is the measures of central tendency?
Definition
  • describes the population sample(descriptive statistics)
  • useful as a shorthand
  • describes the most typical subject
Term
examples of measures of central tendancy
Definition
mean, median, and mode
Term
what measure of central tendancy is the only one that can be used for nominal data?
Definition
Mode-b/c it is just stating what the most common score is
Term
what is the mode?
Definition

the most common score

all levels of measurement

may be more than 1 mode

Term
what is median?
Definition

the value occuring at the midpoint when the data is arranged in order of magnitude

useful for skewed distributions

ordinal, interval or ratio data

Term
what is the mean?
Definition

the sum of the scores divided by the number of subjects (mathematical average)

interval or ratio level data

Term

parameters describe _____

 

statistics describes_____

Definition

parameters- populations

statistics -samples

Term
use ____ in the denominator in the equation for calculating sd because using __ underestimates the dispersion for small sample sizes
Definition
use n-1, not n
Term

greek letters are used to denote_____

latin letters are used to denote_____

Definition

greek-paramenters

latin-statistics

 

Term
what is the preferred measure of central tendancy for skewed distribution?
Definition
median
Term
µ
Definition
population mean
Term
σ
Definition
the population standard deviation
Term

__

X

Definition
sample mean
Term
s or sd
Definition
standard deviation
Term
positive skew is to the
Definition
skewed to the right
Term
negative skew is skewed to the ___
Definition
left
Term
formula for range
Definition
max-min
Term
formula for variance
Definition
s2
Term
if the sample is trimmed what does this mean?
Definition
outlying scores are dropped
Term

if original distribution is trimmed by 10% what does this mean?

 

Definition
5% trimmed on each side of curve
Term
if a mean is winsorized what does this mean?
Definition
20% on each side dropped and replaced by the remaining highest and lowest number, this will often make the mean lower than the median
Term
in a bar chart how is data seperated?
Definition
each bar or segment represents one category and is seperated from the others
Term
bar charts are useful for ____ and _____ data
Definition
nominal and ordinal
Term
in a histogram what do the segments represent?
Definition
the bars or segments touch and represent ranges rather than single values-intervals
Term
histograms are useful for what type of data?
Definition
interval and ratio level data
Term
a skewness of <___ is ok
Definition
<2
Term
kurtosis
Definition
flattened part of the peak
Term

in normal distribution -1 to +1 is____%

-2 to +2 is____%

-3to +3 is ____%

Definition

65%

95+%

>99%

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