A. Translate the argument provided in this prompt into formal logic and then use the truth-tree decision procedure (relying on Proof Tools or pencil/pen and paper) to determine whether the argument is deductively valid or invalid (entailment / non-entailment). b. If the argument is invalid (a case of non-entailment), determine an assignment of truth values (interpretation) to the propositional letters that would show the argument to be invalid (non-entailment).

What is the difference between an observational study and an​ experiment? choose the correct answer below. a. in an​ experiment, a treatment is applied to part of a population and responses are observed. in an observational​ study, a researcher measures characteristics of interest of a part of a population but does not change existing conditions. b. in an​ experiment, a treatment is applied to an entire population and responses are observed. in an observational​ study, a researcher measures characteristics of interest of an entire population but does not change existing conditions. c. in an​ experiment, a researcher measures characteristics of interest of a part of a population but does not change existing conditions. in an observational​ study, a treatment is applied to part of a population and responses are observed. d. in an​ experiment, a researcher measures characteristics of interest of an entire population but does not change existing conditions. in an observational​ study, a treatment is applied to an entire population and responses are observed.