--- title: "Is an automatic or manual transmission better for MPG?" author: "Jesús Pestana Puerta" date: "06/19/2014" output:   pdf_document: default ---  Executive summary =================  This work focuses on determining whether the type of transmission of a car, automatic or manual, does affect its efficiency, which is measured in miles per galon (mpg). This study uses statistical methods on data acquired from real cars. The data used in the analysis  was extracted from the 1974 Motor Trend US magazine, and corresponds to 32 automobiles (1973–74 models) and 10 variables of interest.   Our analysis leads to two main conclusions:    - The first is that this data does not show a statistically significant contribution of the type of transmission to the vehicle's efficiency, with $p_{value} = 0.9089474$.     - The second is that in order to answer the motivating question of this study and ascertain which type of transmission is more efficient, it is required to gather more data. Our currently available data suffers from a fundamental flaw: most of the recorded automatic cars are of big size and horse power, while most of the recored manual cars are of small size and horse power.      Thus, this study requires to be replicated on a new dataset with information on automatic and manual transmission cars of similar size and horse power, which should have data on all the range of engine powers.