Question

Stats help please?

Which of the following are correct?

I. One purpose of a double-blind study is to control for researcher bias and placebo effect
II. The main purpose of randomizing individuals to treatment groups is to control for bias
III. Replication is used to help reduce chance variation in experiments.

A. I and II only
B. I, II, and III
C. III only
D. I only
E. II only

Answer 1

@rational i think they're all true, can i get your opinion please?

Answer 2

yes they all look true to me
also check with @amistre64 @perl

Answer 3

@Mimi_x3 is good with stats too

Answer 4

thanks!

Answer 5

The first one is not correct because of "One purpose of a double-blind study is to control for researcher bias". Placebo affect is not indicated on double-blind study.

Answer 6

II is correct.

Answer 7

III is wrong. replication is the repetition of an experimental condition so that the variability associated with the phenomenon can be estimated. ASTM, in standard E1847, defines replication as "the repetition of the set of all the treatment combinations to be compared in an experiment. Each of the repetitions is called a replicate."

Replication is not the same as repeated measurements of \(\color {red}{THE~~ SAME}\) item: they are dealt with differently in statistical experimental design

Answer 8

@loser66 I kinda disagree with what you have said

Answer 9

Replication is when you repeat the experiment multiple times on diff groups. The objective is to reduce the error of the variation or otherwise known as chance variation. When choosing a sample, our variation may not represent the actual population variation. This may be due to the fact that our sample does not include outliers. Therefore we repeat the process on multiple groups to ensure that the variation actually mirrors the population variation with minimal error.

Hence I would conclude that all 3 options are correct