What is Variable: Definition and 1000 Discussions

A variable star is a star whose brightness as seen from Earth (its apparent magnitude) fluctuates.
This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are classified as either:

Intrinsic variables, whose luminosity actually changes; for example, because the star periodically swells and shrinks.
Extrinsic variables, whose apparent changes in brightness are due to changes in the amount of their light that can reach Earth; for example, because the star has an orbiting companion that sometimes eclipses it.Many, possibly most, stars have at least some variation in luminosity: the energy output of our Sun, for example, varies by about 0.1% over an 11-year solar cycle.

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  1. MatinSAR

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  2. I

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  3. M

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  4. Lay1

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  5. M

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  6. F

    I Sample space, outcome, event, random variable, probability...

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  7. F

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  8. ananonanunes

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  9. DaveC426913

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  10. C

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  11. H

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  12. S

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  13. M

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  14. F

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  15. sol47739

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  16. Spector989

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  17. A

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  18. S

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  19. K

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  20. MatinSAR

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  21. F

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  22. adamaero

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  23. K

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  24. F

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  25. S

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  26. Eclair_de_XII

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  27. F

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  28. bikashdaga

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  29. rudransh verma

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  30. A

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  31. rudransh verma

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  32. marcophys

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  33. T

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  34. shivajikobardan

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  35. shivajikobardan

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  36. J

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  37. M

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  38. S

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  39. M

    MHB Understanding Random Variable Mapping and Probability Functions

    Hey! :giggle: What does it mean to give the mapping for a random variable? Do we have to give the outcome space and the probability function? Does it hold that $X: ( \Omega, P)\mapsto \mathbb{R}$ ? :unsure:
  40. docnet

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  41. chwala

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  42. M

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  43. M

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  44. S

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  45. K

    I An equation invariant under change of variable

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  46. M

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  47. K

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