Three of the medical doctors surveyed by a biochemist prefer his newly approved brand X as compared to the leading medical the biochemist use these results to write the TV advertisement shown. Is the inference valid?

No

Step-by-step explanation:

In propositional logic, an argumentcan only be valid IFF

(1) it is inconsistent to assert all the premises and the negation of the conclusion (semantic validity), and/or

(2) the rules of inference allow you to derive the conclusion from the premises (syntactic validity).

In the case of the medical doctors, the leading medical officer I'd against, therefore violating rule (1) as stated above.

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