# Add option to PTC task to correct for sigma clipping bias

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## Details

• Type: Story
• Status: To Do
• Resolution: Unresolved
• Fix Version/s: None
• Component/s:
• Labels:
None
• Team:
Data Release Production
• Urgent?:
No

## Description

When sigma-clipping to calculate the mean and variances, biases are potentially introduced at both the high and low flux ends, and should be corrected for somehow.

It's not clear how to do this well, but this ticket notes at least considering how we should approach it.

## Activity

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Nicholas Mondrik added a comment -

To be pedantic, I will note that bias is introduced in the variance estimate at all flux levels (not just high or low), but bias is introduced in the mean estimate only when the distribution is significantly non-symmetric (high- or low-flux, as Merlin said).

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Nicholas Mondrik added a comment - To be pedantic, I will note that bias is introduced in the variance estimate at all flux levels (not just high or low), but bias is introduced in the mean estimate only when the distribution is significantly non-symmetric (high- or low-flux, as Merlin said).
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Merlin Fisher-Levine added a comment -

That is indeed exactly what I meant to say

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Merlin Fisher-Levine added a comment - That is indeed exactly what I meant to say

## People

• Assignee:
Unassigned
Reporter:
Merlin Fisher-Levine
Watchers:
Andrés Alejandro Plazas Malagón, John Swinbank, Merlin Fisher-Levine, Nicholas Mondrik, Seth Digel