SOLUTION: A student doing an internship at a large research firm collected the following data, representing all of the studies the firm had conducted over the past 3 years. What is the p

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Question 1143688: A student doing an internship at a large research firm collected the following data, representing all of the studies the firm had conducted over the past 3 years.

What is the probability that the study did not use randomization, if we already know that the study was a retrospective observational study?

Randomization? Retrospective Observational Prospective Observational Experiment Total
Yes 7 28 35 70
No 53 62 115 230
Total 60 90 150 300

0.88

0.85

0.27
Answer by ikleyn(52890)   (Show Source):
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A student doing an internship at a large research firm collected the following data, representing all of the studies
the firm had conducted over the past 3 years.

What is the probability that the study did not use randomization, if we already know that the study was
a retrospective observational study?

Randomization? Retrospective Observational Prospective Observational Experiment Total Yes 7 28 35 70 No 53 62 115 230 Total 60 90 150 300 Answer options 0.88 0.85 0.27

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            What you see above -- is your post.

            Please pay attention on   how I EDITED (formatted) it   TO MAKE SENSE.

ANSWER. P = = 0.88 (correct with 2 decimal places) Although the formula is SELF-EXPLANATORY, I will give some explanation. Go to the column "Retrospective Observational", take there two appropriate numbers "53" and "60" and make a ratio.