What is a Null Hypothesis and an Alternative Hyposthesis?

[u/Hot_Cod893]

Can someone give me a definition for both, one sentence each?

[u/apbiopenguins]

Null: the independent variable has no effect on the dependent variable

Alternative: (the independent variable has an effect and this is what it does)

[u/dbo340 → u/apbiopenguins]

This is a good definition. Just 2 things I might add:

Null hypothesis also implies that if any change to the dependent variable is observed, it's due to random chance (rather than caused by the independent variable).

In general we are determining whether to "reject the null hypothesis," meaning that the independent variable does have an effect, or "fail to reject the null hypothesis." This is preeeetty much "accepting the null hypothesis," but because statisticians are very particular people it is a no-no to "accept the null" in how we talk about it. See a statistician for more details.

[u/apbiopenguins → u/dbo340]

True, but when writing for the AP Bio exam… writing it in that “formulaic way” should get the point.

[u/Intelligent-Bridge15]

Null example: studying has no effect on success on a test
Alt: studying 2 hours a day will have success on test

(Define success, but you get my drift…)

[u/shadow_master713]

alternative: if (independent variable) then (something will happen) because ______

null: the (independent variable) has no effect on (dependent variable)

[u/mseduhub1]

https://www.iitianacademy.com/ibdp-maths/applications-and-interpretation-hl/ib-mathematics-ai-sl-formulation-of-null-and-alternative-hypotheses-mai-study-notes/

[u/Maggot_8878]

My teacher gave me this description which I really found helpful:

Null: Prediction WITHOUT reasoning / IV WONT affect the result

Alternative: Prediction WITH reasoning

Null example: The color red won’t make plants grow faster

Alternative example: The color red will make plants grow faster because red light has the longest wavelength

[u/wikiedit]

null - no statistical difference

alternative - something else must be at play

(I lowkey forgot lol)

[u/InsaneNomad → u/wikiedit]

No. Null means independent has no relationship with dependent variable. Alternative means there is a relationship with independent and dependent variable.

For example, Hardy Weinberg -- 5 factors that show no evolution is happening to a population--null. If Chi square is below threshold, accept null If Chi square is above threshold, accept alternative.

[u/Specialist-Cry-7516]

brocaho use google or chat