11) Ch11: Data Analysis

Question 1

Descriptive Stats

Answer 1

Used to summarize patterns/characteristics in the data to describe the distribution of data points

• Include sum, mean, mode, standard deviation, and frequency of nominal variables
• Typically performed on all measured/recorded variables in a study

Question 2

Correlative Statistics

Answer 2

Used to calculate how variables are similar or relate to each other/ Strength of relationships btwn variables

• Includes Pearson Product Moment Correlation Coefficient, ICC, Spearman Rank Correlation Coefficient

Question 3

Pearson Product Moment Correlation Coefficient

Answer 3

Used to determine if the scores of 2 variables vary together

Question 4

ICC

Answer 4

Used to determine if the scores of 2 variables vary together and how closely those scores are matched

Question 5

Spearman Rank Correlation Coefficient

Answer 5

Used to determine if the scores of 2 variables of ordinal data vary together

• Same as Pearson except used w/ordinal data

Question 6

Comparative Stats

Answer 6

Used to compare 2+ sample groups on 1+ measured attributes; Describe how variables are different; Determine whether 2+ groups of data are different and suggest cause-and-effect relationships between an intervention and an outcome

• Includes t-tests, ANOVA, ANCOVA, MANOVA (Parametric), Mann-Whitney U Test, and Wilcoxen Signed-Ranks Test(Nonparametric)

Question 7

Independent T-Test

Answer 7

Compares the means of 2 groups in which there aren’t any repeated measures

• Assumes a normal distribution of the sample and random selection & assignment

Question 8

Paired T-Test

Answer 8

Compares the means of 2 repeated measures from the same sample group or from matched pairs of subjects

Question 9

ANOVA

Answer 9

Compares the means of 3+ groups on a single measure or 3+ repeated measures on the same group

Question 10

ANCOVA

Answer 10

Compares the means of 2+ groups on 2 measures or repeated measures on 2+ groups

Question 11

MANOVA

Answer 11

Compares 3+ independent variables

Question 12

Mann-Whitney U Test

Answer 12

Compares the rank order of scores from 2 groups on an independent variable

Question 13

Wilcoxen Rank Sum Test

Answer 13

Compares the rank order of scores from 2 groups on an independent variable w/sample sizes <30 subjects

• Same as Mann-Whitney but used for sample sizes <30 subjects

Question 14

Kruskal-Wallis ANOVA

Answer 14

Compares rank or ordinal data from 3+ groups

Question 15

Clinical Significance

Answer 15

Differences in the measured variable that result in useful changes

Question 16

Statistical Significance

Answer 16

Occurs when the data analysis results in a number that exceeds level of chance

Question 17

Sampling Bias

Answer 17

Imbalance of characteristics in a group of pt’s studied so the group is not a true representation of the typical defined subject

Question 18

Procedure Variability

Answer 18

Range of methods used by clinicians to perform the same task or to achieve the same endpoint

• In clinical practice, interventions are not done exactly the same for each pt bc you have to adjust based on pt-specific factors

Question 19

Measurement Bias

Answer 19

Imbalance in the data resulting from the choice of a measurement tool, from inherent errors associated w/the application or recording of the measure, from limits of tool construction, and variations in documentation on the measure

• Approach to tx’ing acute LBP → Exam processes from one clinic may yield a broad array of tests and measures whereas another clinic may yield a smaller different set based on their certifications
• Neither way is necessarily better than the other but it might make comparison tougher → Need to interpret results, inputs, and processes w/the understanding that they might be unique and that causes limitations

Question 20

Historical Bias

Answer 20

Imbalance in the data resulting from an event that happens outside of the pt care interaction, which might influence some aspect of pt care or outcomes

Question 21

Experimental Bias

Answer 21

Imbalance of data that occurs when participants or investigators have expectations for outcomes bc they know who or what is being studied so their objectivity may be consciously or unconsciously be swayed

• Can influence statistical interpretation bc when a certain outcome is anticipated, the investigator may only see that outcome and fail to recognize other outcomes of the data set