I. Solve the given problem for testing hypotheses using the stepwise method. Use a One-tailed test and 0.01 alpha level of significance. A study of the effect of caffeine on muscle metabolism used eighteen male volunteers who each underwent aim 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 subjects resperatory exchange ratio (RER) was measured. (RER is the ratio of CO2 produced to O2 consumed and is an indicator of whether energy is being obtained from carbohydrates or fats). The question of interest to the experiments was whether, on average, caffeine changes RER.
Correlation
Correlation defines a relationship between two independent variables. It tells the degree to which variables move in relation to each other. When two sets of data are related to each other, there is a correlation between them.
Linear Correlation
A correlation is used to determine the relationships between numerical and categorical variables. In other words, it is an indicator of how things are connected to one another. The correlation analysis is the study of how variables are related.
Regression Analysis
Regression analysis is a statistical method in which it estimates the relationship between a dependent variable and one or more independent variable. In simple terms dependent variable is called as outcome variable and independent variable is called as predictors. Regression analysis is one of the methods to find the trends in data. The independent variable used in Regression analysis is named Predictor variable. It offers data of an associated dependent variable regarding a particular outcome.
I. Solve the given problem for testing hypotheses using the stepwise method. Use a One-tailed test and 0.01 alpha level of significance.
A study of the effect of caffeine on muscle metabolism used eighteen male volunteers who each underwent aim 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 subjects resperatory exchange ratio (RER) was measured. (RER is the ratio of CO2 produced to O2 consumed and is an indicator of whether energy is being obtained from carbohydrates or fats).
The question of interest to the experiments was whether, on average, caffeine changes RER.
The two populations being compared are "men who have not taken caffeine" and men who have taken caffeine". If caffeine has no effect on RER the two stes of data can be regarded as having come from the same population.
RER ( %)
Placebo Caffeine
105 96
119 99
100 94
97 89
96 96
101 93
94 88
95 105
98 88
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