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What does large sample mean for two population means?
In the context of estimating or testing hypotheses concerning two population means, “large” samples means that both samples are large. A confidence interval for the difference in two population means is computed using a formula in the same fashion as was done for a single population mean.
When do you use the term baseline equivalence?
The WWC uses the term “baseline equivalence” when determining whether the intervention and comparison groups had key observed characteristics that were similar enough (“equivalent”) before the start of the intervention (at “baseline”).
How to compare two populations by mean and standard deviation?
Each population has a mean and a standard deviation. We arbitrarily label one population as Population 1 and the other as Population 2, and subscript the parameters with the numbers 1 and 2 to tell them apart. We draw a random sample from Population 1 and label the sample statistics it yields with the subscript 1.
How big does a sample have to be to be an independent statistic?
The test statistic has the standard normal distribution. The samples must be independent, and each sample must be large: n1 ≥ 30 and n2 ≥ 30. Refer to Example 9.1.1 concerning the mean satisfaction levels of customers of two competing cable television companies.
What’s the difference between a growth rate and percent change?
Important to note is the fact that neither the growth rates nor the percent changes were equal in the two decades for either population. As the tables show, there were higher percentage increases and greater rates of growth among both these populations in the 1990s than in the 2000s.
How can I compare groups with unequal sample sizes?
I have two datasets containing Z-score data. However both of them are of highly different sizes, i.e one has 500 samples while the other has 4. I want to determine if the differences between the samples is statistically significant.