Hi there. I'm a humanitarian assistance manager, forced by circumstances to dust off my knowledge of probability sampling, due to the current circumstances. As above, is it possible to use a Stratified/Cluster Sampling method? The strata would be province level. The clusters would be geographic areas where assistance is being delivered. If it helps, see map. The orange boundaries are provinces and the greenish boundaries are our areas of operations. Many thanks!
https://preview.redd.it/v8q2nmrpcuu51.jpg?width=1435&format=pjpg&auto=webp&s=ba006c801642795275473c9edb5d96283432d972
For a question I'm doing, I'm asked to list the sampling procedure of selecting students to take a survey related to refurnishing the canteen of a 6th form college as they enter the canteen & the advantages + disadvantages of using it.
I thought the sampling procedure would be cluster sampling, instead of opportunity sampling, because it was the answer to another question I did which asked me to identify the sampling procedure the police would use if they wanted to find the average speed of cars travelling in the outside lane of a motorway. This is because the average speed changes depending on the time period so I would need to take a cluster of different time periods. Can't the same concept be applied as students enter the canteen? Depending on the time & day, you will get different types of students so in order for the survey to be representative of the student population you would need to take a cluster sample from different time periods.
Anything I missed? Maybe my definition of opportunity sampling is wrong or its just a form of cluster sampling & I wasn't specific enough. Here is how I defined it in my notes:
Opportunity sampling
- This is used when circumstances make a sample readily available. E.g., the delegates at a conference of hospital doctors are used as a sample to investigate the opinions of hospital doctors in general on a particular issue. This can obviously bias the results and opportunity sampling is often viewed as the weakest form of sampling.
- It can be useful for social scientists who want to study behaviours of particular groups of people, such as criminals, where research will lead to individual case studies rather than results which are applied to the whole population.
- It can also be useful for an initial pilot study before a wider investigation is carried out.
Title explains it. Basically, is the main difference just the fact that in cluster sampling, the random numbers that are assigned (and then sampled) simply include more people due to clustering? No other big difference?
Hi friends, I'm new to scRNA-seq and this community has been really helpful so far with technical questions and programming struggles. I've been using bioconductor scater/scran and this fantastic book https://bioconductor.org/books/release/OSCA/ and now I can see cell clusters. Woot!
I realized have a conceptual/statistics question and I don't know what the field consensus is. Say I am learning about different cell types in a tissue: there's no experimental group, I am just subjecting the tissue to dissociation and scRNA-seq and analysis and then looking at clusters. If I repeat this experiment multiple times and end up with 8 biological replicates (~2000 cells each) from the same tissue, should I pool all of the cells together (now I'd have 16000), correct for batch effects, and treat the pool as a very large sample, or should I keep the 8 samples separate always and see if the same clusters emerge each time? Is there a way to test for cluster consistency between batches (and is this the relevant metric that people test for)? Or my 3rd idea would be to use 1-2 of the samples to define the genes that define the clusters, and then use those definitions to cluster the remaining 6-7 samples (or a pooled version of those 6-7 samples) so that I don't double-dip?
I'm also interested in how your answer would change if there were a control and experimental group(s) and I wanted to compare how cell populations were different (in size, number, or gene expression) between multiple groups.
With all of this, if you can point me toward a good primer on this topic I'm more than happy to read it if you don't feel like explaining to me. And because I do actually have multiple batches of cells from the same tissue, packages or functions that are particularly helpful for these challenges are also warmly welcomed.
Thanks!
Howdy! I have quite a few testers and I though about storing them all together but then I thought having that close a proximity would cause some diffusion between all of them over time. My bottles all stay in a wooden box but have some space, they aren't butted up against each other.
Any input appreciated.
With stratified sampling, if you want to sample the population of the United states, you would take a random sample of people from each state.
With Cluster sampling, you would group all the states into random groups of 2 or more states, and randomly sample one or more of these groups, and all the people in it would be your sample ?
