Chi squared in inheritance: Using chi-squared to prove Mendelian genetics.

[@madooha8966]

congrats miss on hitting 1k subs 🙌

[@MissEstruchBiology]

Thank you!! 😁

[@saher8476]

@@MissEstruchBiology she hit 50 k

[@areebt3222]

hello miss, for the test surely you should say the 'there is more than 5% probability that the difference in results are due to chance', not 'there is more than 5% probability that the results are due to chance' because the results themselves are not due to chance, it is the difference that is important.

[@callummullaney8052]

When A-level psychology comes in clutch bro

[@MissEstruchBiology]

ha nice!

[@theodoresweger4948]

Very good thanks. gave me a workout, did it manually and with my HP prime...

[@jidahs563]

How do you calculate expected value without any expected ratio given? E.g 26:51:19

[@HotWheelsGT]

Late but the mendelian genetics ratio for monohybrid is always 3:1 and for dihybrid its always 9:3:3:1

[@phoenixraven2779]

Doesn't the null hypothesis get rejected if the value of chi-sqaured is less than the critical value as the likelihood the differences between expected and observed being due to chance is less than 5%?

[@MissEstruchBiology]

Hello, No, the chi squared value has to exceed the critical value to reject the null hypothesis. It is a threshold that has to be exceeded to show the difference is significant and therefore reject the null hypothesis. Hope that helps

[@phoenixraven2779]

@@MissEstruchBiology Thank you so much for the response, yes I understand now - I was confused by a markscheme but it turned out the question was referring to probability not the critical value. Also, thanks for all your videos, the information you provide is so clear and concise and I refer to you for everything!

[@vivekgordon9316]

Hi, surely it should be a less then a 5% probality that the results are due to chance at the chi2 value is less then critical value

[@MissEstruchBiology]

if the chi squared value doesn't meet or exceed the critical value, then it means there is more than 5% probability the difference is due to chance (it is not a significant difference)

[@vivekgordon9316]

@@MissEstruchBiology okay thanks

[@tafadzwapenyisa9263]

You answered my question 🥰

[@MissEstruchBiology]

No problem 😊

[@archjanasivasuthan6252]

Hi, thank you for this video! Towards the end of your video, you mentioned that because the calculated value is less than the critical value, it means that it is more likely that the results are due to chance. Doesn't this mean that the results aren't reliable, thus there might be significant difference, please?

[@MissEstruchBiology]

Hello, If the results are due to chance then there is not a significant difference. In the case of inheritance, that means there is not a significant difference between what you expected and observed, indicating the results did match Mendelian genetics. Hope that helps

[@nifemiagunbiade2159]

How did you get the table containing the critical values and the degrees of freedom

[@MissEstruchBiology]

In what sense do you mean?

[@nifemiagunbiade2159]

@@MissEstruchBiology will the table be given to us or it won’t

[@uwotm8770]

@@nifemiagunbiade2159 you have to pay for it

[@JT-ip6hx]

@@nifemiagunbiade2159 you always get it in the question

[@hafenikores1631]

What if you rounded off the chi-square value? In your case round it off to 3.2? Is it incorrect to do so?

[@MissEstruchBiology]

Hello, Avoid rounding during the calculation as this can affect the accuracy.

[@AS-mw6pw]

Should the conclusion not be: ‘there is more than 95% probability that the results are due to chance’ or ‘there is less than 5% probability that the results are NOT due to chance’? Saying ‘there is more than 5% probability that the results are due to chance’ doesn’t really tell us much, surely, because it implies that there could be a high probability that the results aren’t due to chance, but also that there could be a low probability that the results are due to chance (anywhere from 5% to 100%). From what I understand, If the Calculated value < Critical value: Accept null hypothesis, Because there is a less than 5% probability that the differences between the observed and expected values were NOT due to chance. (Alternatively: Because there is a more than 95% probability that the differences between the observed and expected values were due to chance). If Calculated value > Critical value: Reject Null hypothesis, Accept alternative hypothesis, Because there is a less than 5% probability that the differences between the observed and expected results were due to chance. (Alternatively: Because there is a more than 95% probability that the differences between the observed and expected values were NOT due to chance). I might be misunderstanding it, but from what I understand, saying ‘there is a more than 5% probability that the results are due to chance’ is the wrong conclusion in any scenario.

[@MissEstruchBiology]

Hello I understand what your saying, but this is how it is used at A-level Biology. The reason being is we use the statistics only to be able to conclude whether the difference is significant or not. Therefore , anything over 5% probability due to chance shows it is not significant. So it doesn't matter whether is 6% or 99% probability its due to chance as they both give the same conclusion that the difference is not significant. I hope that helps clarify.

[@AS-mw6pw]

@@MissEstruchBiology Hi, I can see where I was going wrong now. I appreciate the response it was very helpful :)

[@MissEstruchBiology]

That's ok , glad to have helped 😊

[@SavyStat]

Hello ma, I was thinking if the degree of freedom is 1 then the Yate continuity correction formula should be used Ma'am?

[@thirshansubaskaran5488]

Thank you

[@MissEstruchBiology]

No problem ! You're welcome 😊

[@rasha.hijazi8482]

Lovee thiss

[@MissEstruchBiology]

Thank you!!!

[@faisalabdulqader3533]

What do uou do if you don’t know the expected

[@MissEstruchBiology]

there would be information given in the question to work it out, or if not you assume 50:50.

[@faizalrazali4839]

kau kenal peaky blinders

[@tafadzwapenyisa9263]

You answered my question 🥰

[@MissEstruchBiology]

So glad 😁

[@Simi.g]

thank you

[@MissEstruchBiology]

you're welcome 😊