Randomized Trials: Sample Size and Distribution Comparison

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What is a key concept in the context of randomized trials?

Marked improvement in sheep

Color of the beads

Sample size (correct)

Distribution of beads in jars

What is the main concern when conducting trials of new agents?

Sample size estimation (correct)

Color of the beads

Distribution of beads in jars

Marked improvement in sheep

What is the rationale for requiring the registration of new randomized trials in advance?

To calculate efficacy in a randomized trial

To define the four major phases of randomized trials

To draw meaningful conclusions about the study population (correct)

To discuss the distribution of beads in jars

What is a common mistake made by investigators conducting studies?

Not estimating the required sample size before the study Signup and view all the answers

What are the four major phases of randomized trials used by the US Food and Drug Administration for evaluating new drugs?

Not mentioned in the text Signup and view all the answers

What is the main objective of the sample size discussion in the given text?

To ascertain if the distribution of beads by color differs in jars A and B Signup and view all the answers

What is the purpose of taking a sample of 10 beads from each jar?

To reach a conclusion about the color distribution of all 100 beads in each jar Signup and view all the answers

Why is it not possible to conclude that 90% of the beads in jar A are blue and 10% are white based on the 10-bead sample?

Because it is highly unlikely that the sample represents the entire jar accurately Signup and view all the answers

What is a plausible reason for not being able to conclude that 20% of the beads in jar B are blue and 80% are white?

The 10-bead sample was not taken accurately Signup and view all the answers

Why is it significant to consider additional samples when drawing conclusions about the color distribution of beads in jars A and B?

To reduce the impact of random chance and improve accuracy Signup and view all the answers

What is the term used to describe the probability of correctly identifying a difference between therapies if in reality they are different?

Power Signup and view all the answers

Which term designates the probability of making a type II error?

Beta Signup and view all the answers

What does the 1 - beta represent in the context of the study's decision-making process?

Power Signup and view all the answers

In the context of the study, what is the significance of beta?

Probability of making a type II error Signup and view all the answers

What is the term used to describe the probability of concluding, in error, that the therapies do not differ?

Type I error Signup and view all the answers

What does the total of all probabilities equal in the given context?

$1 - \beta$ Signup and view all the answers

What is the probability that we will correctly decide on the basis of our study that the therapies differ if there is a difference?

$1 - \beta$ Signup and view all the answers

What does the term 'power' tell us about the study?

How likely our study is to miss a difference if one exists Signup and view all the answers

In the context of this study, what does alpha represent?

Probability of making a type I error Signup and view all the answers