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.
These eight numbers have the average (mean) of 5: To calculate the population standard deviation, first find the difference of each number in the list from the mean. Then square the result of each difference: Next, find the average of these values (sum divided by the number of numbers). Last, take the square root: The answer is the population standard deviation. The formula is only true if the eight numbers we started with are the whole group. If they are only a part of the group picked at random, then we should use 7 (which is n â 1) instead of 8 (which is n) in the bottom (denominator) of the second-to-last step.