State What the Given Confidence Interval Suggests About the Two

question 95

Essay

State what the given confidence interval suggests about the two population means.
-When testing for a 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) comes from a population with a mean that is different from the mean for the
placebo population? Explain. $$\begin{array} { | l | l | l | l | } \hline & \text { t-Test: Two Sample for Means } & & \\\hline 1 & & \text { Variable 1 } & \text { Variable 2 } \\\hline 2 & \text { Mean } & 65.10738 & 66.18251 \\\hline 3 & \text { Known Variance } & 8.102938 & 10.27387 \\\hline 4 & \text { Observations } & 50 & 50 \\\hline 5 & \text { Hypothesized Mean Difference } & 0 & \\\hline 6 & \mathrm { t } & - 1.773417 & \\\hline 7 & \mathrm { P } ( \mathrm { T } < = \mathrm { t } ) \text { one-tail } & 0.0384 & \\\hline 8 & \mathrm { TCritical } \mathrm { one-tail } & 1.644853 & \\\hline 9 & \mathrm { P } ( \text { T<=t) two-tail } & 0.0768 & \\\hline 10 & \text { tCritical two-tail } & 1.959961 & \\\hline\end{array}$$

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Definitions:

µ = 145

A statement indicating that the mean (average) of a particular set of data or population is equal to 145.

Standard Error

The standard deviation of the sampling distribution of a statistic, typically the mean, reflecting the variation of the sampling statistic over different samples.

Mean

The arithmetic average of a set of numbers, obtained by dividing the sum of these numbers by their quantity.

Z-statistic

A statistic used to determine the difference between an observed statistic and its hypothesized population parameter, measured in units of the standard deviation.