final exam Flashcards
T- Test
the difference between two means (e.g., experimental vs. control, men vs women). Independent variable is nominal and the dependent variable is Continuous.
t- test example
Two means regular discharge mothers and early discharge mothers
Chase tested the difference in the mean birth weights of infants whose mothers either had or had not participated in a special prenatal education pro
Paired t-test (dependent group tests)
If means of a single group of people measured before and after an intervention were being compare
ANOVA:
Tests the mean group differences between 3 or more groups (F-value)
ANOVA example
Hutchingson compared mean pre-op anxiety levels in three groups of patients with different types of cancer.
Repeated measured ANOVA (RM ANOVA)
when means being compared are means at different points in time.(eg mean blood pressure at 2,4 and 6h after surgery)
Chi-Square:
X2 Used to test hypotheses about differences in proportions as in a cross-tabulation. Hint: compares data presented as PERCENTAGES %
chi-square example
Tucker tested the difference in the proportion of smokers vs nonsmokers who had tried an illegal drug
Messi compared the percentage of patients who had a fall in two hospital units, one of which had implemented a new patient safety protocol.
Correlations (r-value)
To test the existence and strength of a relationship between two variables. Both variables are continuous.
correlations (r-value) example
Powell tested the significance of the relationship between scores on a functional ability test and a cognitive performance test in nursing home residents.
P value
a number, calculated from a statistical test, that describes how likely you are to have found a particular set of observations if the null hypothesis were true.
P values are used in hypothesis testing to help decide whether to reject the null hypothesis.
IV:
(“I” for influence, intervention, or exposure and “C” for comparison group).
The presumed cause of the dependent variable)
DV
(“O” for outcome that a researcher is trying to understand, explain, or predict)- can also be the outcome that is being measured by variables.
Presumed effect of an independent variable
IV & DV example
smoking (IV) → lung cancer (DV)
** EXAMPLE: In a study of how different doses (IV) of a drug affect the severity of symptoms, a researcher could compare the frequency and intensity of symptoms (DV) when different doses are administered
A study was done to find if different tire treads (IV) affect the braking distance (DV) of a car
Pico components
P: patient or population
I: influence, intervention,
C: comparison group
O: outcome
nested sample
research design in which levels of one factor (say, Factor B) are hierarchically subsumed under (or nested within) levels of another factor (say, Factor A)
Girardi’s Grocery Store wants to determine how a redesign of its store layout will impact its most loyal customers
Convenience (volunteer) sampling;
not preferred approach but economical, the weakest form of sampling due to sample bias
Recruit participants by placing a notice on a bulletin board or on the internet
Snowball: (network sampling):
sample might be restricted to a small network of acquaintances. Asking early informants to make referrals.
May be affected by whether the referring sample member trusted the researcher and truly wanted to cooperate.
Purposive sample
researchers deliberately choose the cases that will best contribute to the study.
Allie explored nightmares in hospitalized children and recruited both boys and girls from different socioeconomic and ethnic backgrounds
Randomized
The experimenter assigns participants to a control or experimental condition on a random basis.
Confounding variable
A variable that is extraneous to the research question and that confounds understanding of the relationship between the independent and dependent variables; confounding variables can be controlled in the research design or through statistical procedures.
Anonymity
the most secure means of protecting confidentiality occurs when the researcher cannot link participants to their data.
e.g. A questionnaire is sent to a group of nursing home residents and was returned without any identifying information, responses would be anonymous.
Confidentiality
this is a pledge that any information participants provide will not be publicly reported in a manner that identifies them and will not be made accessible to others.
e.g. the names, ages, and occupations of study participants whose interviews are contained in the research report are not divulged.
Informed Consent
means that participants have adequate information about the study, comprehend the information, and have the power of free choice, enabling them to consent to or decline participation voluntarily.
Right determination and the right to full disclosure are the two elements on which informed consent is based
Non-probability sampling
does not involve selection of elements at random; is rarely representative of the population.
Quota sampling
identifying population strata and figuring out how many people are needed from each stratum (or convenience from each stratum).
strongest sampling
Consecutive sampling
recruiting all people from an accessible population over a specific time interval, Is likely to yield a representative sample
The first 100 patients admitted to the ER.
Probability sampling
all probability samples involve random selection of elements: each element has an equal, independent chance of being selected
Simple random sampling:
the most basic probability; researchers establish a sampling frame– a list of population elements.
If nursing students from the University of Connecticut were the population, a student roster would be the sampling frame.
Stratified sampling
the population is first divided into two or more strata, from which elements are then randomly selected
Systematic sampling
is a probability sampling involving the selection of every kth case from a list, such as every 10th person on a patient list
HYPOTHESIS
states the actual prediction of a relationship. Must contain terms that indicate a relationship (more than, less than, different from, associated with)
Are formally tested through statistical analysis.
Researchers make predictions about variables
Are never proven or disproved
Are supported or rejected
Directional hypothesis
specifies the expected direction of the relationship between variables.
Older patients are more likely to fall than younger patients.”
The risk of falling increases with the age of the patient.
Nondirectional hypothesis
does not stipulate the direction of the relationship.
“There is a relationship between a patient’s age and the likelihood of falling.
Older patients differ from younger ones with respect to their fall risk.”
Null hypothesis
states that there is no relationship between the independent and dependent variables; just as likely.
“Older patients are just as likely as younger patients to fall.
Phenomenology
Relies on a very small sample (often 10 or fewer)
Guided by two principles (1) Participants must have experienced a phenomenon of interest. (2) They must be able to articulate what it is like to have lived that experience.
Ethnography
Mining with many members of the culture –a “big net” approach
informal conversations with 25-50 informants
Multiple interviews with a smaller number of key informants
Typically involved sampling things as well as people
Grounded Theory
Typically involved samples of 20-30 people
Selection of participants who can best contribute to an emerging theory (usually theoretical sampling)
Theoretical sampling
is a process of data collection for generating theory whereby the analyst jointly collects codes and analyses data and decides what data to collect next and where to find them, in order to develop a theory as it emerges.
Mean
equals the sum of all values divided by the number of participants; what we usually call the average;
Mode:
the mode is the number that occurs most frequently in a distribution.
Median:
the point in a distribution that divides scores in half;
Nominal:
lowest level of measurement; involves using numbers simply to categorize attributes. Does NOT have quantitative meaning.
Attributes are only names
Cannot be treated mathematically
→ Example: Male=21; Female=24; Undergraduate=1; Graduate=2; Sex, nationality, blood type, clinical diagnosis
Ordinal:
ranks people on a attribute; numbers indicate rank ordered observations;
→ Example: ADL’s (signifies increments, but does not specify how much greater one level is from another), smoke status, pain, functional status, and manual muscle test
Attributes are rank ordered but distances between points in the scale are not equal.
Apgar scores are ordinal
Interval:
ranks people on an attribute and specifies the distance between them;
→ Example: temperature, IQ, calendar years, scores on a depression scale.
Distance is meaningful
Does not have a true zero (can be negative)
The mean is usually the statistic reported
Scores on a psychosocial scales are considered interval-level measurements
Ratio
:highest level; ratio scales, unlike interval scales, have a meaningful zero and provide information about the absolute magnitude of the attribute.
→Example: weight, age, and blood pressure, ratio measurement, BMI respiration
Mean is usually a statistic reported
The mean is usually the statistic reported for which type or types of measure?
C) Interval measures
D) Ratio measures
The mode is an index of which of the following?
B) Central tendency
The measure of central tendency that is most stable is which of the following?
C) Mean
The measure of variability that takes into account all score values is which of the following?
D) Standard deviation
A researcher compared the mean anxiety levels of patients in a soothing music group, a massage group, or a control group. The statistical procedure that was likely used to test group differences is which of the following?
ANOVA
In analysis of covariance, a covariate is generally which of the following?
A confounding variable
To test mean differences among related groups over time with at least three different points of data collection, you would use which of the following?
Repeated measures ANOVA
Testing the significance of difference in two group means is done with which of the following?
Independent groups t-test
In an analysis of variance (ANOVA), which of the following contrasts variation between groups with variation within groups
F ratio
