Category: Statistics

How do you know whether something is a trend or not? First, we need to define a trend. A trend is: a general direction in which something is developing or changing Second, we should mathematically define and be able to detect a trend. Trend analysis (and any kind of statistical analysis) is generally not something…

Vito asks, “Let’s assume we have the joint probability distributions of A and B. In that scenario, is it possible that A causes B, but A and B are not correlated?” This is possible and even probable when you have missing data, especially if the missing data is also partially causal. Some examples: – Distributions…

Jessica asks, “When it comes to marketing data science, I’ve got very good business knowledge, but lack of the technical side. any advice?” The first question you have to ask is whether you need the hands-on skills or just knowledge of what’s possible. The second question is what skills you already have. Remember that in…

Phil asks, “How do you determine a large enough sample size for things like our survey? I always thought 10% sample would be enough, but you seemed to think that’s not true?” It depends on the size of the overall population. The smaller the population, the larger the sample you need. It also depends on…

Jessica asks, “How would you differentiate hypothesis formation and searching for relevant variables WITHOUT “data snooping”?” Data snooping, or more commonly known as curve fitting or data dredging, is when you build a hypothesis to fit the data. The way to avoid this is by using evidence not included in the dataset you used to…