jamovi

In other words:
1. What does the formula "ignore_missing=1" actually do to the data? Is the mean calculated without the missing value, or is the missing value substituted for a value of 1? Sorry, as mentioned I don't understand the language of this software. I'm very new to data analysis and Jamovi ...

Hi Jonathon, thanks for your suggestion. Just a couple of follow-up questions:
a) I'm not sure how this formula would work. Would I need to change all the 99s to 1s for it to work? Would it ensure that a mean based on all other scores and excluding the 99s (i.e. not substituting them for 0)?
b ...

I’m working with a spreadsheet containing ‘99’ values – these are not missing values, but rather, where participants have chosen that a particular item in a scale is not applicable to them.

I’ve been asked to create Mean scores for several scales including some of these 99 (not applicable) values ...