z test for two sample mean - SERP Analysis

https://www.analystsoft.com/en/products/statplus/content/help/analysis_basic_statistics_two_sample_z-test.html

http://www.stat.ucla.edu/~cochran/stat10/winter/lectures/lect21.html

https://www.statology.org/two-sample-z-test/

https://www.theopeneducator.com/doe/hypothesis-Testing-Inferential-Statistics-Analysis-of-Variance-ANOVA/Two-Sample-Z-Test

https://sixsigmastudyguide.com/two-sample-z-hypothesis-tests/

https://www.xlstat.com/solutions/features/two-sample-t-and-z-tests

https://www.investopedia.com/terms/z/z-test.asp

https://www.statskingdom.com/120MeanNormal2.html

https://www.solver.com/z-test-two-sample-means

https://vitalflux.com/two-samples-z-test-for-means-formula-examples/