Consider a Study in Which Two Sets of 20 Mice

question 45

Essay

Consider a study in which two sets of 20 mice were given different amounts of caffeine in their drinking water. Members of the control group got none and members of the experimental group received 0.01% caffeine in their water. Their activity levels were measured using the mean number of minutes each mouse spent running on the wheel in their cage over a series of 14 nights.
Control treatment: mean = 305 minutes, standard deviation = 40 minutes
Caffeine treatment: mean = 340 minutes, standard deviation = 70 minutes
Because the variances may be different, use the Welch's t-test approach for this data.
Perform a complete two-sample t-test. Summarize your results with a statement about the 95% confidence interval for the difference between the means, draw a figure showing the 95% confidence intervals for each treatment, present the t-test statistic and P-value for the two-sample test, and state your conclusion with regard to accepting or rejecting the null hypothesis and what this means for the effects of caffeine on mouse activity levels.

---

Definitions:

Tetanus

A bacterial infection characterized by muscle stiffness and spasms, caused by the bacterium Clostridium tetani.

Arrhythmias

Irregular heartbeats resulting from abnormalities in the heart’s electrical impulses, which can affect heart function.

Isovolumetric Contraction

A phase of the cardiac cycle during which the ventricles contract with no change in blood volume, because all heart valves are closed.

Pressure

The force exerted by a substance per unit area on another substance or on a surface, measured in units such as Pascals.