how do you know if a sample size is large enough?

Question

In regards to quantatative research

Answer 1

The sample should be representative of the group at large, which means it shoudl contain approximately the same sex, ethnic and socio-econtomic differences as the large group. The larger the group, the larger the sample. You can not do research on all teenagers based on twenty kids. You can do research on a particular high school based on twenty kids.

Answer 2

> Calculate your sample size
What is the right population size for your survey?
The amount of people your company should survey is based on several different things. Begin by determining the number of people in your target market. Then determine how accurate you wish your data to be. Generally, most statisticians use a confidence level of 95% with a margin or error ranging from +/- 3 to +/ - 5 points. Of course, your budget as well as the bias of your market can also dictate how many people you should survey.
Is this a good enough example?

Answer 3

I'm guessing you are a techer making sample sizes for young children. In this case each sample size is only large enough if it is exactly the same as every single other sample size.

Answer 4

A sample size can be any size it is a sample ( small quantity to try product ) and it is free. All samples of that product should be of same size/quantity so it's usually just enough for you to try and make a decision on if to purchase or to get product, from what you have tried.

Answer 5

You must know the variance. Also one variance collection of samples. Then there are of the formulas in order to see the dimension of a champion (90% or 95% reliable). Most statisticians use a confidence level of 95%

Answer 6

target size = population for which you have made your hypothesis.
sample should be nearly 10% random selection from the total.

Answer 7

That depends on how many groups you want to study, and what phenomena you want to study. In general, the more subjects you have in your study, the better.