How would I go about comparing two populations (A and B) with unequal sample sizes.
Sample size of A, SA: 10,000 Sample Size of B, SB: 2000
My goals are:
To use data visualization tools to study relationships between the variables of each sample (Example: bar graph, histograms, scatter plots)
To compare the means of both the samples.
a. By hypothesis testing
b. By simply estimating the mean of each sample such that the sample size of A and B are equal (Example: The sample size of A and B are equal (say 2000) with a mean of 40 and 35 respectively).
Since the sample sizes are very different, I do not know:
a. If I must be worried about such a huge difference in sample sizes (I have not checked but seems like the variances are unequal too).
b. Is sampling or weighting recommended?
By sampling I mean: randomly selecting 2000 observations from SA
By weighting I mean: Assign a constant to the data to increase emphasis of the information from SB.
If there are statistical tests robust to such a huge difference in sample sizes
Do data visualization tools (like scatter plots and bar graphs) render reliable results when sample sizes are highly unequal?