Regression Models of MPG in Automobiles

Synopsis

In this report we are interested to know if automatic or manual transmission is better for MPG using the mtcars dataset and to quantify this result. The complication is that other variables also affect the MPG. In our best linear regression model, we see that weight and \(\frac{1}{4}\) mile time influence the MPG and therefore transmission alone cannot be used to determine the better MPG.

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Effect of Vitamin C Dose and Supplement Type on Tooth Growth

Synopsis

This is an analysis of the ToothGrowth dataset on guinea pigs available in the R standard installation. We first do a summary and exploratory analysis to see what the data includes. We then perform some statistical inference with confidence intervals and hypothesis testing to see which dose and supplement of vitamin C is more efficient in tooth growth. Assumptions are made to state our conclusions. We can state that orange juice is the better supplement for tooth growth in two of the three dosages. However for the highest dose, we cannot see any advantage of orange juice over ascorbic acid. In general, tooth growth increases with dose.

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