# Tag Info

### What does it mean for observations to be uncorrelated and have constant variance?

Random variables VS observations. Strictly speaking, there are random variables (which take values in $\mathbb{R}$) and realizations of these random variables (which are elements of $\mathbb{R}$). ...
• 431
Accepted

### What does it mean for observations to be uncorrelated and have constant variance?

These are assumptions made for certain models to ensure certain properties, like valid test statistics. There's a great overview here. The key word here is assumption. These need not hold up in real ...
• 12.8k

### What does it mean for observations to be uncorrelated and have constant variance?

$y_i$'s are not just real numbers. They are random variable. Specifically, the simplest linear model assumes y_i = x_i^T\beta+\varepsilon_i,\quad \varepsilon_i\overset{iid}{\sim}\mathcal{N}(0,\sigma^...
• 305

### Generating highly non-independent random samples

No, you can't! Let's look at an example from your code. ...
• 41.5k

### Multivariable analysis for an ordinal dependent variable

It is crucial to select a good method for checking the proportional odds (PO) assumption. Which method did you use? Please note that the Bland test is very anti-conservative and that SAS should not ...
• 95.7k
1 vote
Accepted

### Regression with dependent observations of only one individual

My Y variable will likely be binary (agrees/disagrees) or on a Likert scale (1-5) I'd recommend the Likert scale since it's more informative. For analysis you can use an ordinal logistic model. https:...
• 2,842

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