Well I just realized this is definitely in the wrong forum can someone please delete this thread? I can't seem to find an option for that myself..

Sorry if this is in the wrong thread. I am trying to determine if a research project is feasible to conduct by calculating the sample size needed.

I am seeing if a new protocol is more effective than an established protocol via an randomized controlled trial. Outcomes will be measured via a definition we established for a "complication" which can be a variety of things. A previous study stated that the complication rate for the established protocol is about 92%. I am trying to see how many people I would need to follow in order to see a reduction by 20% in the complication rate, so 72% complication rate. My power is going to be 80%.

I've been trying to use PS (independent t-test) with an alpha=0.05, power=0.8, delta(difference in mean)=0.2, sigma(STD)=?, m(ratio of control to experimental)= 1

but it requires me to input a standard deviation of which I don't have since I haven't measured anything and the previous study did not give a STD. Everything else I think I have except the STD.

I'm really rusty with statistics so any help would be appreciated. Sorry if this post is confusing / not clear.

Sorry if this is in the wrong thread. I am trying to determine if a research project is feasible to conduct by calculating the sample size needed.

I am seeing if a new protocol is more effective than an established protocol via an randomized controlled trial. Outcomes will be measured via a definition we established for a "complication" which can be a variety of things. A previous study stated that the complication rate for the established protocol is about 92%. I am trying to see how many people I would need to follow in order to see a reduction by 20% in the complication rate, so 72% complication rate. My power is going to be 80%.

I've been trying to use PS (independent t-test) with an alpha=0.05, power=0.8, delta(difference in mean)=0.2, sigma(STD)=?, m(ratio of control to experimental)= 1

but it requires me to input a standard deviation of which I don't have since I haven't measured anything and the previous study did not give a STD. Everything else I think I have except the STD.

I'm really rusty with statistics so any help would be appreciated. Sorry if this post is confusing / not clear.

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