Research stuff

Question 1

The positive likelihood ratio can be described as:

Answer 1

Probability that a person with the disease tested positive

Question 1

What statistical test would be most appropriate to determine if there is a statistical significance in hip abduction strength in subjects with patellofemoral pain compared to subjects without knee pain?

Answer 1

ndependent t-test is the most commonly used method to evaluate the differences in means between two groups. The groups can be independent (e.g., blood pressure of patients who were given a drug vs. a control group who received a placebo) or dependent (e.g., blood pressure of patients “before” vs. “after” they received a drug, see below). Theoretically, the t-test can be used even if the sample sizes are very small (e.g., as small as 10; some researchers claim that even smaller n’s are possible), as long as the variables are approximately normally distributed and the variation of scores in the two groups is not reliably different

Question 2

What is the measure of Central Tendency?

Answer 2

median, mean, mode- Summarizes the mid-point of a data set

Question 3

What are Type 1 errors?

Answer 3

False Positives
when there is no difference but one is found.
P-values are set to minimize this at the level the research team is comfortable with, typically, 0.05.
This indicates that values greater than this will result in acceptance of the null, and leaves only very strong findings left to reject the null
you conclude that the drug intervention improved symptoms when it actually didn’t. These improvements could have arisen from other random factors or measurement errors.

Question 4

What do P values do?

Answer 4

-minimize false positives at the level the research team is comfortable with, typically, 0.05.
This indicates that values greater than this will result in acceptance of the null, and leaves only very strong findings left to reject the null

Question 5

What is a risk of a low powered research study?

Answer 5

A low powered study can result in non-significant findings,
or a Type II error - false Negative-

Question 6

Type II error?

Answer 6

False Negative
Example: the test result says you don’t have coronavirus, but you actually do.
you conclude that the drug intervention didn’t improve symptoms when it actually did. Your study may have missed key indicators of improvements or attributed any improvements to other factors instead.

Question 7

Sensitivity

Answer 7

is the proportion of those with a positive test given that they have the condition being tested for. When calculating the sensitivity, you only need be concerned with the 5 patients who have bacteremia. All patients with bacteremai had leukocyte counts great than 10, so the sensitivity of a leukocyte count greater than 10 is 100%.
the proportion of actual positives which are correctly identified as such

Question 8

Specificity

Answer 8

is the proportion of those with a negative test given that they do not have the condition. Here, only those whose blood cultures are negative need be considered. When a leukocyte count of 10 is used as the cut-off for a positive test, of the 15 without bacteremia, 6 will correctly test negative, for a specificity of 6/15, or 40%.

Question 9

Prevalence

Answer 9

is the proportion of patients who have a condition at a particular time. In the sample of 20 patients, 5 had bacteremia. The prevalence is 5/20, or 25%.

Question 10

What is ANOVA statistic used for?

Answer 10

COMPARISON OF 3+ TREATMENT GROUPS

ANOVA checks the impact of one or more factors by comparing the means of different samples
it checks if the means of two or more groups are significantly different from each other

to determine of three or more population means are equal. It is useful because there are many scenarios for which we do not want to know the exact difference between population means, only if they are equivalent. It is also a relatively simple method to calculate if the population means are roughly equal or vastly different. The ANOVA test requires that the populations being tested are normally distributed, have equal variances and that the samples are independent of each other.

Question 11

What are the hierarchy of Evidence levels?

Answer 11

1a.. Systematic Review of RCT that DO NOT have statistically variation in results
1b. Individual RCT with NARROW CONFIDENCE INTERVAL
1c. all or none- study in which all or some patient died before treatment available- now none die
2a. Systematic Review of CORHORT studies that DO NOT have variation in results
2b. Individual Cohort study inducing low qualityRTC with <80% follow up
2c. outcomes research- nonexperiemental research that studies care in :real world” clinical conditions
3a.Systematic review of case control studies
3b. Indv case control study
4. Case study
5. Expert opinion without explicit critical appraisal

Question 12

What is KAPPA statics used for?

Answer 12

assess reliability of fixed or ordinal data
ex a study to test the reliability of a new pain rating scale based on integer values reflecting a patient’s pain beliefs.

Question 13

Good value for Postive LR?

Answer 13

BIGGER THE BETTER- 10 = conclusive shift

Question 14

Good Value for Negative LR?

Answer 14

WANT TO BE AS CLOSE TO 0 AS POSSIBLE
<0.1 excellent for ruling out
<2.1, moderate for ruling out

Question 15

if a negative or positive LR is 1 what does that mean?

Answer 15

BAD- NO CHANGE AT ALL

Question 16

What is the prevalence if there are 200 ppl in a study and 100 of them have the condition?

Answer 16

50%
prevalence= # ppl with condition/ total ppl
100/200= 50%

Question 17

What are the 4 desired components of good evidence ?

Answer 17

1. addresses specific question you are trying to answer
2. participants have similar characteristics to patients that question is about
3. published in peer reviewed journal
4. context and/or technique consistent with current health care

Question 18

Predictive validity

Answer 18

refer to a test’s ability to predict outcomes or offer information about a prognosis.

Question 19

External validity

Answer 19

The type of validity which deals with the degree to which the results of a trial can be generalized to different subjects and settings

Question 20

Define functional limitations?

Answer 20

occur when impairments result in a restriction of the ability to perform a physical action, task, or activity in an efficient, typically expected or competent manner

Question 21

Discriminative validity

Answer 21

the ability of a test to determine one form of a disorder from another. In this case, this test is able to detect anterior instability from posterior or multidirectional instability, making it a discriminative test

Question 22

What constitutes a “disability”?

Answer 22

If a functional limitation caused the patient to be unable to participate in his normal social behavior (exa. his normal group of friends all interact as members of a running club) it could cause ‘disability’.

Question 23

impairment:

Answer 23

Achilles tendinopathy (pathology) which is the underlying cause of pain with the required strong contraction of the ankle plantar flexors at toe off during running gait (impairment)

Question 24

functional limitation

Answer 24

unable to run

Question 25

A physical therapist is interested in determining how many people who actually have a sacroiliac dysfunction actually test positive for a given special test designed to detect SI problems. This therapist is interested in

Answer 25

Positive predictive value

Question 26

a good screening test is primarily concerned with minimizing false negatives,

Question 27

Specificity measures the proportion of negatives which are correctly identified.

Question 28

A physical therapist is interested in determining how many people who actually have a sacroiliac dysfunction actually test positive for a given special test designed to detect SI problems. This therapist is interested in

Answer 28

Positive Predictive Value

Question 29

TYPE 1 ERROR

Answer 29

False Alarm, False Positive
ex. using a treatment that is no better than the alternative

Question 30

TYPE 2 ERROR

Answer 30

False negative
at treatment that was reported no different ,but in fact was a better treatment

Question 31

Hawthorns effect

Answer 31

subject’s knowledge of being part of a study affects the performance

Question 32

What is an almost perfect Kappa score?

Answer 32

.81-1.0

Question 33

What is substantial kappa agreement

Answer 33

.61-.81

Question 34

Alpha Level

Answer 34

level of statistical significant, risk of Type 1 error

Question 35

Beta Level

Answer 35

probability of making Type 2 error

Question 36

how well a test measures the concept it was designed to evaluate.

Answer 36

construct validity

Question 37

indicates the amount of agreement between two different assessments.

Answer 37

concurrent validity

Question 38

It is a subjective assessment by experts based on experience about whether the measure reflects its intended assessment, and the research community generally considers the weakest form of validity testing because it is not based on objective observation.

Answer 38

Face validity

Question 39

refers to verification of data elements against some reference criterion determined to be valid (i.e., the gold standard). Examples include verification of data elements obtained through automated search strategies of electronic health records (EHRs) compared with manual review of the same medical records (i.e., the gold standard). Concurrent validity and predictive validity are forms of criterion validity.

Answer 39

Criterion validity

Question 39

refers to the degree to which multiple measures/indicators of a single underlying concept are interrelated. Examples include measurement of correlations between a measure score and other indicators of processes related to the target outcome or multiple target outcomes with similar processes.

Answer 39

Convergent validity

Question 40

examines the variation across multiple comparison groups (e.g., measured entities). The measure developer demonstrates discriminant validity by showing that the measure can differentiate between disparate groups that it should theoretically be able to distinguish.

Answer 40

Discriminant/contrasted groups validity

Question 41

Predictive validity refers to the ability of measure scores to predict scores of other related measures or outcomes in the future, particularly if the original measure scores predict a subsequent patient-level outcome of undisputed importance (e.g., death, permanent disability). Predictive validity also refers to scores on the same measure for other groups at the same point in time.

Answer 41

Predictive validity