# Happy model Assignment 2, Course 4

**URL:** <https://community.deeplearning.ai/t/happy-model-assignment-2-course-4/19210>\
**Category:** Convolutional Neural Networks\
**Tags:** coursera-platform\
**Created:** [July 5, 2021, 8:40am UTC](https://community.deeplearning.ai/t/happy-model-assignment-2-course-4/19210 "2021-07-05T08:40:13Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Shashankk20](https://avatars.discourse-cdn.com/v4/letter/s/e495f1/32.png) [@Shashankk20](https://community.deeplearning.ai/u/Shashankk20)\
**Post date:** [July 5, 2021, 8:40am UTC](https://community.deeplearning.ai/t/happy-model-assignment-2-course-4/19210/1 "2021-07-05T08:40:13Z")

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We apply batch normalization in happy model on axis = 3, what is this axis? what does it signify?

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**Author:** ![XpRienzo](https://sea1.discourse-cdn.com/dlai/user_avatar/community.deeplearning.ai/xprienzo/32/51_2.png) [@XpRienzo](https://community.deeplearning.ai/u/XpRienzo)\
**Post date:** [July 7, 2021, 6:57am UTC](https://community.deeplearning.ai/t/happy-model-assignment-2-course-4/19210/2 "2021-07-07T06:57:41Z")

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For our dataset here, the axis 0 is the batch, 1 and 2 are the dimensions and axis 3 is channel. So applying batch normalisation on axis 3 normalises it along the channels. For to why it’s normalised along the channel, you can read [this thread](https://community.deeplearning.ai/t/week-2-what-is-the-meaning-of-axis-3-in-the-batchnormalization/589/2)