What is multicollinearity in multiple regression?

When independent variables are highly correlated with each other...

When should non-parametric tests be used?

When data doesn't meet the assumptions for parametric tests.

What is the purpose of using controls in a study?

To isolate the effect of the independent variable and minimize bias.

What does a line graph best visualize?

Trends over time or model-predicted values.

What is blinding in research?

A method to prevent bias by ensuring participants and/or researchers do...

What is the primary purpose of scientific research?

To identify the truth in a world of information and misinformation.

What can happen in healthcare if someone believes misinformation due to poor statistical understanding?

They may make harmful decisions

What does critical appraisal evaluate?

Validity, importance, and applicability of research findings.

List three characteristics of a good hypothesis.

Clear and specific, testable and measurable, based on existing knowledge.

What is subjective probability?

A belief-based probability that is updated as new data becomes available...

List the 5 steps of Evidence-Based Practice.

Ask, Acquire, Appraise, Apply, Assess

What is Positive Predictive Value (PPV)?

The probability a person actually has the disease if the test is positive.

What is empirical evidence?

Information gathered through direct observation

What is theoretical probability?

Probability based on models and assumptions without experiments (e...

Why is ethics essential in science?

Because science is based on the moral principle of telling the truth

What does a Pearson correlation coefficient (r) of +1 indicate?

A perfect positive linear relationship between two variables.

Define Absolute Risk (AR).

The actual probability of an event occurring in a group over time.

What are nominal data?

Categorical data with no intrinsic order, such as blood type or eye color.

What is a null hypothesis (H₀)?

There is no statistically significant relationship between varaiables

Which of the following are anecdotal evidence?

"My uncle smoked his entire life and he never got lung cancer", "My friend took peppermint oil and their vision improved."

What does the slope (b) in a regression equation represent?

The expected change in Y for a 1-unit increase in X.

What is the formula for Positive Likelihood Ratio (LR+)?

Sensitivity / (1 - Specificity)

What does specificity measure in a diagnostic test?

The probability that a test correctly identifies someone without the dis...

What is the binomial distribution used for?

To model the number of successes in a fixed number of independent trials.

What does Evidence-Based Practice (EBP) integrate?

Research evidence, clinical expertise, and patient preferences.

How does sample size affect statistical power?

Larger sample sizes increase statistical power.

What does it mean if p ≤ α?

Reject the null hypothesis; result is statistically significant.

When is Spearman’s correlation preferred over Pearson’s?

When the data is ordinal or not normally distributed.

Define independent and dependent variables.

Independent variables are manipulated to observe effects...

What does HARKing stand for?

Hypothesizing after the results are known.

Why is anecdotal evidence not sufficient in scientific research?

It is not systematically collected., Highly prone to bias.

What are ordinal data?

Categorical data with ranked order, like pain scale or cancer stage.

Give an example of how statistics can be applied in optometry.

Evaluate treatment effectiveness, Optimize business strategy

What are discrete data?

Countable numerical data, such as number of missed doses.

What is an alternative hypothesis (H₁)?

There is a statistically significant relationship between varaiables

What is conditional probability?

The probability of an event given that another event has already occurred.

What is the Bayesian interpretation of probability?

Probability as a measure of belief updated with new information.

What is the main difference between correlation and regression?

Correlation describes association...

What does sensitivity measure in a diagnostic test?

The probability that a test correctly identifies someone with the diseas...

What does a probability of 1 represent?

An event is certain to occur (100% likelihood).

Define sensitivity in diagnostic testing.

The probability that a test correctly identifies someone with the diseas...

What does a histogram show?

The frequency distribution of data...

What is a confounding variable?

A factor that distorts the observed relationship between independent and...

Which are steps of the scientific method?

Hypothesis, Questioning, Conclusion, Observation, Data analysis

Define Relative Risk (RR).

The risk in the treatment group divided by the risk in the control group.

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Biostats Midterm Review

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Answers

1
What is multicollinearity in multiple regression?
It helps interpret research data to support clinical choices and busines...
When independent variables are highly correlated with each other...
Probability as a measure of belief updated with new information.
Equal variance of residuals across all levels of the independent variable.
2
When should non-parametric tests be used?
Y = a + bX
The probability of observing your result or more extreme...
When data doesn't meet the assumptions for parametric tests.
"My friend took peppermint oil and their vision improved."
3
What is the purpose of using controls in a study?
Reject the null hypothesis; result is statistically significant.
To isolate the effect of the independent variable and minimize bias.
The accuracy of a diagnostic test
When independent variables are highly correlated with each other...
4
What does a line graph best visualize?
Countable numerical data, such as number of missed doses.
The risk in the treatment group divided by the risk in the control group.
Sensitivity / (1 - Specificity)
Trends over time or model-predicted values.
5
What is the formula for simple linear regression?
Quantitative data showing the relationship between two variables.
Equal variance of residuals across all levels of the independent variable.
Y = a + bX
The probability of an event given that another event has already occurred.
6
What is blinding in research?
Countable numerical data, such as number of missed doses.
Reject the null hypothesis; result is statistically significant.
The accuracy of a diagnostic test
A method to prevent bias by ensuring participants and/or researchers do...
7
What is the primary purpose of scientific research?
To collect data
Get published in high impact journals
To make accurate diagnostic tests
To identify the truth in a world of information and misinformation.
8
What can happen in healthcare if someone believes misinformation due to poor statistical understanding?
They will interpret research data to support clinical choices and business
They may make harmful decisions
Clinical care will be faster
9
What does critical appraisal evaluate?
68% within 1 SD, 95% within 2 SD, 99.7% within 3 SD from the mean.
Validity, importance, and applicability of research findings.
The actual probability of an event occurring in a group over time.
The probability a person actually has the disease if the test is positive.
10
List three characteristics of a good hypothesis.
Because two variables can be associated due to a third factor or coincid...
Trends over time or model-predicted values.
Bimodal distribution.
Clear and specific, testable and measurable, based on existing knowledge.
11
What is subjective probability?
"My friend took peppermint oil and their vision improved."
Probability as a measure of belief updated with new information.
Observational studies do not intervene...
A belief-based probability that is updated as new data becomes available...
12
List the 5 steps of Evidence-Based Practice.
Ask, Acquire, Appraise, Apply, Assess
The accuracy of a diagnostic test
The average distance of data points from the mean.
The expected change in Y for a 1-unit increase in X.
13
What is Positive Predictive Value (PPV)?
A belief-based probability that is updated as new data becomes available...
The probability a person actually has the disease if the test is positive.
Categorical data with ranked order, like pain scale or cancer stage.
A factor that distorts the observed relationship between independent and...
14
What is empirical evidence?
Information gathered through direct observation
Data that has a statistical test performed on it
Data showing the relationship between two variables.
Forming an idea of how an experiment will turn out a priori
15
What is theoretical probability?
The expected change in Y for a 1-unit increase in X.
The actual probability of an event occurring in a group over time.
Clear and specific, testable and measurable, based on existing knowledge.
Probability based on models and assumptions without experiments (e...
16
What LR+ value is considered strong evidence to rule in a disease?
To compare data distributions, identify medians, quartiles, and outliers.
Categorical data with ranked order, like pain scale or cancer stage.
Greater than 10
Ask, Acquire, Appraise, Apply, Assess
17
Why is ethics essential in science?
There are no scientific insights that have resulted from unethical methods
Because science is based on the moral principle of telling the truth
Ethical standards speed up research
Ethics is not essential in science
18
What transformation is useful for right-skewed data?
0.9 or greater
The probability that a test correctly identifies someone without the dis...
Log transformation.
It assumes there is no statistically significant relationship between va...
19
What does a Pearson correlation coefficient (r) of +1 indicate?
Probability as the frequency of an event over many trials.
A perfect positive linear relationship between two variables.
Y = a + bX
Countable numerical data, such as number of missed doses.
20
Define Absolute Risk (AR).
Linearity between variables.
Violations of regression assumptions like linearity or equal variance.
When independent variables are highly correlated with each other...
The actual probability of an event occurring in a group over time.
21
What are nominal data?
Probability based on models and assumptions without experiments (e...
It assumes there is a statistically significant relationship between var...
Correlation describes association...
Categorical data with no intrinsic order, such as blood type or eye color.
22
What is a null hypothesis (H₀)?
Variables are dependent on each other
P(not A) = 1 - P(A)
There is no statistically significant relationship between varaiables
There is a statistically significant relationship between variables
23
Which of the following are anecdotal evidence?
"My uncle smoked his entire life and he never got lung cancer"
"A linear regression shows a positive correlation between two variables"
"My friend took peppermint oil and their vision improved."
"An RCT from JAMA states obesity is correlated with diabetes"
24
What does the slope (b) in a regression equation represent?
The expected change in Y for a 1-unit increase in X.
To isolate the effect of the independent variable and minimize bias.
Probability based on models and assumptions without experiments (e...
"My friend took peppermint oil and their vision improved."
25
What is the formula for Positive Likelihood Ratio (LR+)?
Because two variables can be associated due to a third factor or coincid...
The frequency distribution of data...
To identify the truth in a world of information and misinformation.
Sensitivity / (1 - Specificity)
26
What does specificity measure in a diagnostic test?
Sensitivity / (1 - Specificity)
The probability that a test correctly identifies someone without the dis...
Larger sample sizes increase statistical power.
Log transformation.
27
What is the binomial distribution used for?
When the data is ordinal or not normally distributed.
To model the number of successes in a fixed number of independent trials.
Bimodal distribution.
Categorical data with no intrinsic order, such as blood type or eye color.
28
What does Evidence-Based Practice (EBP) integrate?
Using data to evaluate treatment effectiveness or optimize business stra...
Less than 0.1
Research evidence, clinical expertise, and patient preferences.
It helps interpret research data to support clinical choices and busines...
29
What type of distribution has two peaks?
Clear and specific, testable and measurable, based on existing knowledge.
Countable numerical data, such as number of missed doses.
Greater than 10
Bimodal distribution.
30
How does sample size affect statistical power?
Greater than 10
A variable that distorts the observed relationship between independent a...
P(not A) = 1 - P(A)
Larger sample sizes increase statistical power.
31
What does it mean if p ≤ α?
Less than 0.1
Reject the null hypothesis; result is statistically significant.
To isolate the effect of the independent variable and minimize bias.
Because two variables can be associated due to a third factor or coincid...
32
Name a key assumption of linear regression.
Science relies on moral principles like honesty to ensure valid and reli...
The probability that a test correctly identifies someone without the dis...
Violations of regression assumptions like linearity or equal variance.
Linearity between variables.
33
When is Spearman’s correlation preferred over Pearson’s?
To determine if observed differences are statistically significant or du...
The accuracy of a diagnostic test
Log transformation.
When the data is ordinal or not normally distributed.
34
Define independent and dependent variables.
The frequency distribution of data...
It helps interpret research data to support clinical choices and busines...
Information gathered through direct observation...
Independent variables are manipulated to observe effects...
35
What does HARKing stand for?
Hypothesizing according to recent knowledge
Hypothesizing after the results are known.
Helping at risk kids
The herald angels sing
36
Why is anecdotal evidence not sufficient in scientific research?
It is not systematically collected.
Highly prone to bias.
You always reject the null hypothesis.
37
What are ordinal data?
Measurable numerical data that can take any value within a range...
Categorical data with ranked order, like pain scale or cancer stage.
Observational studies do not intervene...
To model the number of successes in a fixed number of independent trials.
38
Give an example of how statistics can be applied in optometry.
Evaluate treatment effectiveness
Determine if a patient will accept treatment based on their political views
Optimize business strategy
To study social phenomenon, attitudes, and behaviors
39
What are discrete data?
(1 - Sensitivity) / Specificity
Countable numerical data, such as number of missed doses.
Clear and specific, testable and measurable, based on existing knowledge.
It is not systematically collected or analyzed and is highly prone to bias.
40
What is an alternative hypothesis (H₁)?
There is no statistically significant relationship between variables
1 / Absolute Risk Reduction (ARR)
There is a statistically significant relationship between varaiables
Data is normally distributed
41
What is conditional probability?
A variable that distorts the observed relationship between independent a...
Violations of regression assumptions like linearity or equal variance.
The probability of an event given that another event has already occurred.
Ask, Acquire, Appraise, Apply, Assess
42
What is the Bayesian interpretation of probability?
Probability as a measure of belief updated with new information.
To collect...
A method to prevent bias by ensuring participants and/or researchers do...
A factor that distorts the observed relationship between independent and...
43
What is the main difference between correlation and regression?
Correlation describes association...
Bimodal distribution.
Because two variables can be associated due to a third factor or coincid...
It is not systematically collected or analyzed and is highly prone to bias.
44
What does sensitivity measure in a diagnostic test?
Mean, median, and mode.
Probability based on models and assumptions without experiments (e...
Because two variables can be associated due to a third factor or coincid...
The probability that a test correctly identifies someone with the diseas...
45
What does a probability of 1 represent?
An event is certain to occur (100% likelihood).
It makes individuals more educated, productive, efficient, and happier.
Probability based on models and assumptions without experiments (e...
It helps interpret research data to support clinical choices and busines...
46
Define sensitivity in diagnostic testing.
A belief-based probability that is updated as new data becomes available...
Improvement due to expectation rather than the treatment itself.
Violations of regression assumptions like linearity or equal variance.
The probability that a test correctly identifies someone with the diseas...
47
What does a histogram show?
The risk in the treatment group divided by the risk in the control group.
To model the number of successes in a fixed number of independent trials.
It helps interpret research data to support clinical choices and busines...
The frequency distribution of data...
48
What is a confounding variable?
Using data to evaluate treatment effectiveness or optimize business stra...
It helps interpret research data to support clinical choices and busines...
Categorical data with ranked order, like pain scale or cancer stage.
A factor that distorts the observed relationship between independent and...
49
Which are steps of the scientific method?
Statistical significance
Hypothesis
Questioning
Conclusion
Observation
Data analysis
50
Define Relative Risk (RR).
The risk in the treatment group divided by the risk in the control group.
Less than 0.1
To compare data distributions, identify medians, quartiles, and outliers.
The probability a person does not have the disease if the test is negative.
51
What LR- value is considered strong evidence to rule out a disease?
It makes individuals more educated, productive, efficient, and happier.
Less than 0.1
The probability that a test correctly identifies someone without the dis...
The probability of an event given that another event has already occurred.
52
What is the purpose of statistical tests in research?
Larger sample sizes increase statistical power.
(1 - Sensitivity) / Specificity
The probability that a test correctly identifies someone with the diseas...
To determine if observed differences are statistically significant or du...
53
What is the formula for Number Needed to Treat (NNT)?
The frequency distribution of data...
When the data is ordinal or not normally distributed.
To collect...
1 / Absolute Risk Reduction (ARR)
54
Why does science speak in terms of probability and confidence instead of absolute certainty?
Not every data set can fit in a linear curve
Data is ordinal or not normally distributed.
Conclusions are based on evidence and statistical analysis
Absolute certainty is only possible when the entire population is tested
55
What is the complement rule in probability?
Categorical data with no intrinsic order, such as blood type or eye color.
P(not A) = 1 - P(A)
To collect...
(1 - Sensitivity) / Specificity
56
What are continuous data?
Greater than 10
A belief-based probability that is updated as new data becomes available...
Measurable numerical data that can take any value within a range...
68% within 1 SD, 95% within 2 SD, 99.7% within 3 SD from the mean.
57
What kind of data is best visualized with a scatter plot?
Independent variables are manipulated to observe effects...
Trends over time or model-predicted values.
Probability as a measure of belief updated with new information.
Quantitative data showing the relationship between two variables.
58
What is the placebo effect?
The probability of an event given that another event has already occurred.
An event is certain to occur (100% likelihood).
Because two variables can be associated due to a third factor or coincid...
Improvement due to expectation rather than the treatment itself.
59
What is the formula for Negative Likelihood Ratio (LR-)?
Improvement due to expectation rather than the treatment itself.
(1 - Sensitivity) / Specificity
Trends over time or model-predicted values.
Using data to evaluate treatment effectiveness or optimize business stra...
60
What does R² represent in a regression model?
Because scientific conclusions are based on evidence and statistical ana...
Research evidence, clinical expertise, and patient preferences.
The proportion of variance in the dependent variable explained by the in...
To compare data distributions, identify medians, quartiles, and outliers.
61
What is a confounding variable?
A variable that distorts the observed relationship between independent a...
Measurable numerical data that can take any value within a range...
The proportion of variance in the dependent variable explained by the in...
Research evidence, clinical expertise, and patient preferences.
62
What is homoscedasticity in regression?
Equal variance of residuals across all levels of the independent variable.
1 / Absolute Risk Reduction (ARR)
Descriptive statistics summarize data...
Observational studies do not intervene...
63
What is the difference between descriptive and inferential statistics?
Randomization, blinding, or statistical adjustments.
To compare data distributions, identify medians, quartiles, and outliers.
Categorical data with no intrinsic order, such as blood type or eye color.
Descriptive statistics summarize data...
64
Why does correlation not imply causation?
The average distance of data points from the mean.
Because two variables can be associated due to a third factor or coincid...
Using data to evaluate treatment effectiveness or optimize business stra...
Y = a + bX
65
What is the Frequentist interpretation of probability?
Improvement due to expectation rather than the treatment itself.
Using data to evaluate treatment effectiveness or optimize business stra...
It assumes there is a statistically significant relationship between var...
Probability as the frequency of an event over many trials.
66
What is the difference between observational and experimental studies?
The probability a person does not have the disease if the test is negative.
It makes individuals more educated, productive, efficient, and happier.
Ask, Acquire, Appraise, Apply, Assess
Observational studies do not intervene...
67
What AUC value represents outstanding test accuracy?
Log transformation.
The probability that a test correctly identifies someone with the diseas...
0.9 or greater
Violations of regression assumptions like linearity or equal variance.
68
When would you use a boxplot?
0.9 or greater
To compare data distributions, identify medians, quartiles, and outliers.
Probability calculated from actual data or experiments.
It makes individuals more educated, productive, efficient, and happier.
69
What does standard deviation represent?
The average distance of data points from the mean.
Less than 0.1
Greater than 10
Violations of regression assumptions like linearity or equal variance.
70
What is a p-value?
It helps interpret research data to support clinical choices and busines...
The probability of observing your result or more extreme...
Probability as the frequency of an event over many trials.
Because science is based on the moral principle that telling the truth i...
71
What is the primary goal of statistics in scientific research?
To collect...
A method to prevent bias by ensuring participants and/or researchers do...
To avoid HARKing and reduce the risk of false positives.
Categorical data with no intrinsic order, such as blood type or eye color.
72
Name one strategy to reduce bias in a study.
Randomization, blinding, or statistical adjustments.
Because science is based on the moral principle that telling the truth i...
Y = a + bX
It is not systematically collected or analyzed and is highly prone to bias.
73
Why is it important to develop a hypothesis before collecting or analyzing data?
Categorical data has no intrinsic order and need a hypothesis to make sense
Hypotheses are not important as they can bias the experiment
To avoid HARKing and reduce the risk of false positives.
It makes individuals more educated, productive, efficient, and happier.
74
What are the measures of central tendency?
The actual probability of an event occurring in a group over time.
To identify the truth in a world of information and misinformation.
Mean, median, and mode.
To determine if observed differences are statistically significant or du...
75
What does a 95% confidence interval mean?
Observation...
To compare data distributions, identify medians, quartiles, and outliers.
P(A and B) = P(A) × P(B)
It means there's a 95% chance the interval contains the true population...
76
What is Negative Predictive Value (NPV)?
To isolate the effect of the independent variable and minimize bias.
Log transformation.
The probability a person does not have the disease if the test is negative.
Hypothesizing After the Results are Known.
77
What does a residual plot help diagnose?
P(not A) = 1 - P(A)
Violations of regression assumptions like linearity or equal variance.
The accuracy of a diagnostic test
A belief-based probability that is updated as new data becomes available...
78
What does the area under an ROC curve (AUC) indicate?
Probability as a measure of belief updated with new information.
To identify the truth in a world of information and misinformation.
The expected change in Y for a 1-unit increase in X.
The accuracy of a diagnostic test
79
What does the multiplication rule state for independent events?
Countable numerical data, such as number of missed doses.
P(A and B) = P(A) × P(B)
An event is certain to occur (100% likelihood).
When independent variables are highly correlated with each other...
80
Define specificity in diagnostic testing.
A variable that distorts the observed relationship between independent a...
The probability of observing your result or more extreme...
Science relies on moral principles like honesty to ensure valid and reli...
The probability that a test correctly identifies someone without the dis...
81
What is the empirical rule for normal distribution?
It assumes there is a statistically significant relationship between var...
Because two variables can be associated due to a third factor or coincid...
68% within 1 SD, 95% within 2 SD, 99.7% within 3 SD from the mean.
Y = a + bX
82
What is empirical probability?
Correlation describes association...
Probability calculated from actual data or experiments.
When the data is ordinal or not normally distributed.
The actual probability of an event occurring in a group over time.

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