Hello,

I need help with the following lab assignment. More specifically how to input the data into an online calculator and how to interpret the results as well as the information that is in bold at the bottom of the page. Thank you in advance for your help!

Case Study Effect of Caffeine on RER

The respiratory exchange ratio (RER) is the ratio between the amount of carbon dioxide (CO₂) produced in metabolism and oxygen (O₂) used. Calculation of RER is commonly done in conjunction with exercise tests as an indicator that the participants are nearing exhaustion and the limits of their cardio-respiratory system.

A study of the effect of caffeine on muscle metabolism used eighteen male volunteers who each underwent arm exercise tests. Nine of the men were randomly selected to take a capsule containing pure caffeine one hour before the test. The other men received a placebo capsule. During each exercise the subject's respiratory exchange ratio (RER) was measured. (RER is the ratio of CO₂produced to O₂consumed and is an indicator of whether energy is being obtained from carbohydrates or fats).

The question of interest to the experimenter was whether, on average, caffeine changes RER.

The two populations being compared are "men who have taken caffeine" and "men who have not taken caffeine." If caffeine has no effect on RER the two sets of data can be regarded as having come from the same population.

The results were as follows:

Caffeine	Placebo
	96	105
	99	119
	94	100
	89	97
	96	96
	93	101
	88	94
	105	95
	88	98
Mean	94.22	100.56
SD	5.61	7.70

The means show that, on average, caffeine appears to have altered RER from about 100.6% to 94.2%, a change of 6.4%. However, there is a great deal of variation between the data values in both samples and considerable overlap between them. Is the difference between the two means simply due to sampling variation, or does the data provide evidence that caffeine does, on average, change RER? The p-value obtained from an independent samples t-test answers this question.

The t-test tests the null hypothesis that the mean of the caffeine treatment equals the mean of the placebo versus the alternative hypothesis that the mean of caffeine treatment is not equal to the mean of the placebo treatment.

Computer output obtained for the RER data gives the sample means and the 95% confidence interval for the difference between the means.

Use a computer program such as Excel or an online calculator to conduct the statistical test at alpha .05 using the t-statistic with the p-value approach.

There is an online descriptive statistics calculator free for use. It will return the sample mean, variance and standard deviation.

There is an online independent samples t-test calculatorand aGuide to Reporting t-Test Results in APA Stylealso free for use.

State the hypotheses and summarize the results and conclusions:

State the hypotheses in complete statements and statistical symbols.

Report the value of the test statistic and degrees of freedom and whether a one- or two-tailed test was used.

Report the p-value of the test statistic.

Report whether the result is statistically significant.

State the conclusion in APA style.

Paste in a copy or screenshot of the calculator output(s).