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.
Standard Deviation. The Standard Deviation is a measure of how spread out numbers are. You might like to read this simpler page on Standard Deviation first. But here we explain the formulas. The symbol for Standard Deviation is Ï (the Greek letter sigma). This is the formula for Standard Deviation: