Comments - Determining Sample Size in One Picture - Data Science Central2020-06-06T06:31:02Zhttps://www.datasciencecentral.com/profiles/comment/feed?attachedTo=6448529%3ABlogPost%3A809976&xn_auth=no@Frank Deruyck Ah, that's whe…tag:www.datasciencecentral.com,2019-03-22:6448529:Comment:8116852019-03-22T14:11:58.960ZStephanie Glenhttps://www.datasciencecentral.com/profile/StephanieGlen
<p>@Frank Deruyck Ah, that's where it gets complicated! You can't solve for n directly (as you noted). If you use the equation above it (for known std dev) to find "n", you'd have an estimate, but it would be an underestimate. So at this point you'd have a couple of choices: use the calculated "Z" sample size equation as a baseline, and guess a but larger. Or, use software to get "n", then use the equation to check the software's solution. Either way, it's really a guesstimate scenario, because…</p>
<p>@Frank Deruyck Ah, that's where it gets complicated! You can't solve for n directly (as you noted). If you use the equation above it (for known std dev) to find "n", you'd have an estimate, but it would be an underestimate. So at this point you'd have a couple of choices: use the calculated "Z" sample size equation as a baseline, and guess a but larger. Or, use software to get "n", then use the equation to check the software's solution. Either way, it's really a guesstimate scenario, because if your population standard deviation is unknown, you're entering the statistical unknown.</p> @John Williams
I can see why…tag:www.datasciencecentral.com,2019-03-22:6448529:Comment:8115832019-03-22T13:58:01.446ZStephanie Glenhttps://www.datasciencecentral.com/profile/StephanieGlen
<p>@John Williams</p>
<p>I can see why you might think that! However, my intent was merely to show the process with an example. It can be tweaked slightly for many more situations. For example, the process for comparing variances is very, very similar. </p>
<p>@John Williams</p>
<p>I can see why you might think that! However, my intent was merely to show the process with an example. It can be tweaked slightly for many more situations. For example, the process for comparing variances is very, very similar. </p> Hi Stephanie, in sample size…tag:www.datasciencecentral.com,2019-03-22:6448529:Comment:8114562019-03-22T07:00:10.395ZFrank Deruyckhttps://www.datasciencecentral.com/profile/FrankDeruyck
<p>Hi Stephanie, in sample size calculation with unknow standard deviation a t value needs to be specified depending on n however this n is unknown and needs to be computed so how to specify the this t(alpha,n-1) value?</p>
<p>Hi Stephanie, in sample size calculation with unknow standard deviation a t value needs to be specified depending on n however this n is unknown and needs to be computed so how to specify the this t(alpha,n-1) value?</p> Sigh. A misleading title. Sam…tag:www.datasciencecentral.com,2019-03-21:6448529:Comment:8115382019-03-21T21:10:58.312ZJohn Williamshttps://www.datasciencecentral.com/profile/JohnWilliams567
Sigh. A misleading title. Sample size for a difference in two means, not sample size in general. Clickbait at its worst.
Sigh. A misleading title. Sample size for a difference in two means, not sample size in general. Clickbait at its worst.