Yet there is considerable opposition to the use of genetically modified plants for food production and other uses. Genetic engineering offers a time-saving method for producing larger, higher-quality crops with less effort and expense. You are a tomato farmer whose crops are threatened by a persistent species of beetle. 2  Each year, you spend large sums of money for pesticides to protect your crops.
To calculate the variance follow these steps: 1  Work out the Mean (the simple average of the numbers). 2  Then for each number: subtract the Mean and square the result (the squared difference). 3  Then work out the average of those squared differences.
So what people like to do is talk in terms of standard deviation, which is just the square root of the variance, or the square root of sigma squared. And the symbol for the standard deviation is just sigma. So now that we've figured out the variance, it's very easy to figure out the standard deviation of both of these characters. The standard deviation of this first one up here, of this first data set, is going to be the square root of 200.