standard deviation is used to measure risks involved in an investment instrument. Standard deviation provides investors a mathematical basis for decisions to be made regarding their investment in financial market. Standard Deviation is a common term used in deals involving stocks, mutual funds, ETFs and others. Standard Deviation is also known as volatility. It gives a sense of how dispersed the data in a sample is from the mean.
so the way I did this was by adding how much he works per week which is 35 per week. so he works 70 hours in 2 weeks. he earns 10 dollars per hour. so 10 times 70 you get 700 but he spends 50. so 700 minus 50. you get 650. he has 650 dollars left.