When Testing the Difference Between the Means of a Treatment

question 43

Essay

When testing the difference between the means of a treatment group and a placebo group,the computer display below is obtained.Using a 0.05 significance level,is there sufficient evidence to support the claim that the treatment group (variable 1)represents a population whose mean is different from the mean for the untreated population? Explain. $$\begin{array} { | l | l | l | l | } \hline & \text { t-Test: Two Sample for Means } & & \\\hline 1 & & \text { Variable 1 } & \text { Variable 2 } \\\hline 2 & \text { Mean } & 171.6392 & 168.7718 \\\hline 3 & \text { Known Variance } & 47.51672 & 41.08293 \\\hline 4 & \text { Observations } & 50 & 50 \\\hline 5 & \text { Hypothesized Mean Difference } & 0 & \\\hline 6 & \text { t } & 2.154057 & \\\hline 7 & \text { P(T>=t) one-tail } & 0.0158 & \\\hline 8 & \text { TCritical one-tail } & 1.644853 & \\\hline 9 & \text { P(T>=t) two-tail } & 0.0316 & \\\hline 10 & \text { tCritical two-tail } & 1.959961 & \\\hline\end{array}$$

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Definitions:

Directional

Pertaining to or indicating the direction of something, often used in the context of research to suggest a specific trend or relationship.

Research Hypothesis

A statement predicting a significant relationship or difference between two or more variables in a study.

Prediction

The act of making informed guesses about the future values or occurrences based on current data or trends.

Scientific Method

Method of investigation that uses the objective and systematic collection and analysis of empirical data to test theories and hypotheses.