ResearchDsgnStats Exam1

Advantages of EBM

Attempts to increase the likelihood of receiving interventions that are efficacious

Disadvantages of EBM

Many questions lack available evidence.

Characteristics of a Good Research Question- FINER

F - Feasibility

I - Interesting

N - Novel

E - Ethical

R - Relevant

N in FINER

N - Novel

Five Steps of Practicing EBM

1. Ask - develop your answerable questions

2. Acquire (Find) - Efficiently Find best Evidence

3. Appraise - Critically evaluate the evidence for validity and usefulness

4. Apply - use results of the appraisal in your clinical practice

5. Assess (Evaluate) - Evaluate your performance

Five Steps to Practicing EBM Highlighted Answer

Acquire (Find) - Efficiently find the best evidence

Why do you need to know how to practice EBM?

Keep up to date and to apply knowledge necessary for good clinical care

Stay current with relevant literature

Four PICO(T) Questions defined

Therapy - compare two or more interventions for condition

Etiology/Harm - looking for association between an exposure and an outcome

Diagnosis - comparing a new diagnostic test to the reference standard test

Prognosis - given a condition, does a certain factor portend a worse prognsis?

Four PICO(T) questions are...(highlighted word)

foreground questions

Background questions

STEM = What is, Why do, How does...

Statistical Estimation

General method of calculating confidence intervals

Point estimate +/- (critical value)(Standard Error)

Statistical Estimation and Confidence Interval

Increasing the sample size will decrease the width of a confidence interval

Type I (a) error

Rejecting the null when the null is true

When you randomly select a group of 500 people across the US to participate in a study, what is the group you have chosen called?

Sample

For a statistical test where the alpha is set at 0.05 for the level of significance, a p-value of 0.01 should be interpreted as confirmation that ___________.

Small p-values indicated strong evidence AGAINST the null hypothesis

Statistical vs Clinical Significance

Clinical significance - related to whether the finding are clinically or practically meaningful (i.e will they affect practice?)

Statistical significance means that the observed results are unlikely to have occurred due to chance alone, assuming the null hypothesis is true

When a research article is said to have clinical significance, it means the results of the study are unlikely due to chance

Prognosis and Harm/etiology do not have

RCT (random controlled trials)

P values and confidence levels

Confidence level is equivalent to 1 - alpha level. So significance level is 0.05, the corresponding confidence level is 95%. If the p-value is less than your significance (alpha) level, the hypothesis test is statistically significant

What chart is best used to represent proportions or relative quantities of values?

Pie graph

Central Limit Theorem

The distribution of sample means approximates a normal distribution as the sample size gets larger, regardless of the population's distribution

3 main tenants of Central Limit Theorem

1. The mean of all sample means will equal the population mean

2. The standard deviation of the sample means is equal to the standard error of the mean

3. As the sample size increases, the distribution of the sample means approaches the normal distribution (regardless of the underlying distribution of the variable)

IQR for Data = 16.5

Minimum 250HD (vitamin D) level in ng/mL for healthy adolescents in Spring is ~10

Intervention in: On morning rounds in the Hem/Onc unit, a first year resident turns to you for consultation. She wants to discuss options for managing moderate nausea and vomiting that result following chemotherapy. She shares an experience a relative had taking ginger when prochlorperazine didn’t provide effective relief and asks for your input.

Intervention: ginger

Intervention in: In patients with recurrent furunculosis, do prophylactic antibiotics reduce the recurrence rate compared to ‘no treatment’?

Intervention: Prophylactic antibiotics

Which are clinical foreground questions?

•Is 15 minutes of exercise daily more effective than 45 minutes of exercise three times a week in reducing the risk of cardiovascular problems in middle-aged men?

Does fatigue contribute to depression in patients with cancer?

In patients presenting with chest pain, is high-sensitivity troponin more accurate than standard troponin in diagnosing myocardial infarction?