Thanks for your question. Mathematics and statistics play a huge and invaluable role in decision making, particularly in the business environment. This is largely where the use of mathematics/statistics in terms of decision making is focused.
Everything from percentages, ratios, comparison charts and risk analysis is derived from mathematics and is integral to the outcome of any business. People depend heavily on these statistics in order to guide them in the right direction.
Most of the best decisions we make, in business and in general life, are derived from data analysis. More often than not, decisions that are made must be justified by the use of maths and data, in order to solidify the choice and provide a framework for it's potential outcome. Overall, this eliminates the necessity of guessing, makes decision making far more substantial, clarifies problems and outlines how they are to be rectified and provides objective over subjective proof of the best outcome possible. This is integral to the decision making process.
I hope this helps.