dear sir i want to take 90% confidence level , then what will be my sample size ? Available online at http://www.pewinternet.org/Reports/2013/Teens-Social-Media-And-Privacy.aspx (accessed July 2, 2013). Thank you. With the current sample of 100 your margin of error is 8.01% which is really high. I have a population of 23,245 from the tables am required to use a sample size of 370, but I want to use 200 as my sample, can you justify a sample of 200 statistically. Businesses that sell personal computers are interested in the proportion of households in the United States that own personal computers. As such you can be sure that you will have a total sample that is large enough for both profiles. How can I defend the statement that a respins rate of 67% is good and sufficient? Is there a way we can do this? Also, what all variables should be considered? You’ll see how to calculate confidence intervals for population proportion with simple to follow steps. To find out the employee contribution to SOCSO towards their productivity at workplace. I also intend to involve migrant groups from different ethnic groups. If you calculate this in our calculator (bottom part of the page) https://www.checkmarket.com/market-research-resources/sample-size-calculator/, you will see that, with a confidence level of 95%, you obtain a margin of error of 11,32%. A student polls his school to see if students in the school district are for or against the new legislation regarding school uniforms. Using the second part of our calculator you can calculate the margin of error of your sample. There are no formulas or calculations to know your population size. 2) use some relevant quotes from your interviews to highlight some of your findings. I have to determine the needed sample size for a population of 350 for both the 0.01 and the 0.05 significance levels. Because the population is pre-qualified, the incidence rate is 100%. Use the “plus-four” method to find a 96% confidence interval for the true proportion of freshmen at State University who have declared a major. Thanks.How many sample do i need in 1,400,767 population? Hello , I am doing PHD research in e-commerce ,using survey and ,y respondents all general , I want to make my sample size 304 , plz help me to know how I can get my size 304 ? However, if you clearly report this in your analyses and you formulate your conclusions carefully (pointing out it is not representative) I think you should be fine normally. Please advise. Please, I need your guide and help to know whether I should use random sampling or purposive sampling design? And so, what is the formula for the sample size determination and where you make use of the population. The comment to various questions raised have improved my understanding of calculating the sample size. For a smaller margin of error and/or higher confidence level you will need a largere sample. does 384 makes sense for such a large population ? for a population of 5,000 your MoE will be 4,8%, for 10,000 it will be 4,9%, for 1,000,000 there is just a marginal increase to 5,0%. If you know the size of your population (or if you have an estimate) you can use our sample size calculator to calculate your sample size for a given margin of error (commonly 5% is taken) and confidence level (95%). i tried using your SSadjusted = (SS) / 1 + [(SS – 1) / population] formula to adjust the SS based on the population but it still registers about 385… may i request some help on this? Also, make sure that you have a large enough sample if you want to validate latent variables through factor analysis. The confidence interval for the larger sample is narrower than the interval from Example 6. If [latex]\displaystyle{P'}{\sim}{N}[/latex](p, [latex]\displaystyle\sqrt{\frac{{pq}}{{n}}}[/latex]) then the z-score formula is z = [latex]\displaystyle\frac{{p'-p}}{{\sqrt{pqn}}}[/latex]. Just fill in your data and it will calculate the number of samples. as it sounds like use of % is not much recommended. However, I plan to use a self-completion survey which usually has a response of 10% . What do you believe the likely sample proportion to be? Or is it? between 85% and 95% of the population likes the line?