Polyfit function - NaN

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Gina Carts
Gina Carts 2019-3-18
回答： Guillaume 2019-3-18
I have the age and blood measurement of some data. For some people the age is missing and I marked them as NaNs.
When I used the function polyfit to calcualte the slope and intercept it returns NaN values.
How can I deal with a missing data? Ideally I would like to keep the people with missing age.
age=[29, 31, 28, 34, 28, 31, 25, 27, 29, NaN]
measure=[82.2699,65.9515,71.3140,66.6908,76.5600,71.3734,94.6844,90.4026,95.950,97.2310]
>> polyfit(age,measure,1)
>> ans =
NaN NaN
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Gina Carts
Gina Carts 2019-3-18
The NaN was a missing information. Can I put something else instead of NaN or should I remove that person from the sample?
Torsten
Torsten 2019-3-18
Does this person add information to the sample ? I guess, no. So you should remove it from the data analysis.

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Guillaume
Guillaume 2019-3-18
polyfit cannot cope with missing data.So, if you want to use polyfit you have but no choice to remove that missing data.
If the reason for the missing data is completely random, then it's not an issue. If the reason for the missing data is not random, then you'll have to employ statistic methods that are robust to missing data and you need to do some research.

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