Update 22_linear_regression_direct_inverse.py

Update 23_linear_regression_qr_decomposition.py

Merge branch 'main' of github.com:thomasnield/oreilly_math_fundamentals_data_science

update linear algebra slides

Update EXERCISE_SOLUTIONS.md

probability slide corrections

fixes

Merge branch 'main' of github.com:thomasnield/oreilly_math_fundamentals_data_science

more fixes to stats section

Delete ~$03_linear_algebra.pptx

clean up formatting errors in linear algebra

cleanup stats section

reorganize for 4 sections

reorganize for only 4 sections

Update 05_multiple_linear_regression_sklearn.py