I have seen this question in a past paper for AQA where it talks about the value being less than 0.05 and therefore accepting the null hypothesis. Did they do this because their null hypothesis was that there was a statistically significant difference?
thank you so much for the video!! was just if the calculated value was less than the critical value does that mean that the probability is more than 5%? also is P always equal to 0.05?
Hello :) If the calculated value is less than the critical, then yes, there is more than 5% probability that the difference is due to chance. You can have other P values, 0.05 is just the threshold to be able to conclude that there is a significant difference.
so we don't have to learn how to carry out the mathematical side for chi-squared but just be able to interpret information about it ie the p values etc for aqa
yeah that's writs, not for the exam. They make give you the numbers and get you to fill in the observed/expected table if they give you the formula. But almost always its analysis of p value and conclusion
Hi miss, why isn't there a less than 5% probability that the difference between O+E are due to chance when the calculated value is less than the critical value? I'm confused on why it's the other way round!
The critical value is a threshold that the calculated value must meet or exceed. At the p=0.05 critical value, that would mean that if the calculated value was greater than the critical value there is probability it is due to chance is 5% Hope that helps
Thank you so much for the video. It was really helpful! Would this come up in an AS biology exam paper ? I have seen questions about it but i haven't seen any calculations. they were more data analysis than calculation questions.
i think that if it was a paired t test then you’d be looking at the mean number of ivy leaves on the shaded side and light side. but since this is the actual frequencies of the leaves growing on each side compared to an expected ratio, using the chi-squared test is fine
What if our chi-squared value is less than the chi-squared value in the table? Does that mean that there is a high probability of the expected and observed results to be the same and that the null hypothesis can be confirmed?
Hello, Yes, that is correct. It would show there is no significant difference between the expected and observed value and therefor you accept the null hypothesis. Hope that helps :D
Hi i am confused is the calculated value and P value different? I thought if the p value is less than 0.05 then you reject the null hypothesis and it is not significant but for the calculated value if its GREATER than the critical value then you reject the null hypothesis Please help
Hello The calculated and p value are different things. The calculated value is the statistic you have calculated. The p value is used to identify which critical value to compare your calculated value to in order to see if you have a significant difference. If the calculated value is greater/equal to the critical value at p=0.05 then you have a significant difference. I hope that helps.
So if the chi-squared value is greater than the critical value, we reject the null hypothesis, but in statistical testing in maths, a result greater than the critical value means accepting the nulll hypothesis. Why is this different across the two subjects?
you are actually a life saver, I’ve been learning statistics this week and only now do I understand it 😭
they can be so tough to get your head around! Happy it helped ☺️
I literally don't get it
same i’m so lost
This was super helpful, thanks a lot!
So pleased you liked it ☺
Hi, How do I calculate the expected value? Or would this be given in the exam? Thanks
how do we know that the difference between the observed and expected value is large if we are not given the expected value tho?
I have seen this question in a past paper for AQA where it talks about the value being less than 0.05 and therefore accepting the null hypothesis. Did they do this because their null hypothesis was that there was a statistically significant difference?
thank you so much for the video!! was just if the calculated value was less than the critical value does that mean that the probability is more than 5%? also is P always equal to 0.05?
Hello :)
If the calculated value is less than the critical, then yes, there is more than 5% probability that the difference is due to chance.
You can have other P values, 0.05 is just the threshold to be able to conclude that there is a significant difference.
Hi, what are the main Maths skills we need to know for AS biology ?Thanks
Hey they are all listed in the Maths skills section of the specification
omg this makes so much more sense now
is it less than 5% as the p value is 0.05 so 0.05 times by 100=5?
so we don't have to learn how to carry out the mathematical side for chi-squared but just be able to interpret information about it ie the p values etc for aqa
yeah that's writs, not for the exam. They make give you the numbers and get you to fill in the observed/expected table if they give you the formula. But almost always its analysis of p value and conclusion
Hi miss, why isn't there a less than 5% probability that the difference between O+E are due to chance when the calculated value is less than the critical value? I'm confused on why it's the other way round!
The critical value is a threshold that the calculated value must meet or exceed. At the p=0.05 critical value, that would mean that if the calculated value was greater than the critical value there is probability it is due to chance is 5%
Hope that helps
Thank you so much for the video. It was really helpful! Would this come up in an AS biology exam paper ? I have seen questions about it but i haven't seen any calculations. they were more data analysis than calculation questions.
Fabulous always ,Miss Estruch
Thank you! :)
Rizzler
Yooo...man looks older than her😂
Hello, would this test be useful for comparing mean zones of inhibition? I did an experiment testing the efficacy of natural antibiotics.
does shaded and light area mean this is paired student t-test?
i think that if it was a paired t test then you’d be looking at the mean number of ivy leaves on the shaded side and light side. but since this is the actual frequencies of the leaves growing on each side compared to an expected ratio, using the chi-squared test is fine
THANK YOUUU
You're welcome!!!
What if our chi-squared value is less than the chi-squared value in the table? Does that mean that there is a high probability of the expected and observed results to be the same and that the null hypothesis can be confirmed?
Hello,
Yes, that is correct. It would show there is no significant difference between the expected and observed value and therefor you accept the null hypothesis.
Hope that helps :D
Why is there less than 5% probability, not just 5%?
Hi i am confused is the calculated value and P value different? I thought if the p value is less than 0.05 then you reject the null hypothesis and it is not significant but for the calculated value if its GREATER than the critical value then you reject the null hypothesis
Please help
Hello
The calculated and p value are different things.
The calculated value is the statistic you have calculated. The p value is used to identify which critical value to compare your calculated value to in order to see if you have a significant difference.
If the calculated value is greater/equal to the critical value at p=0.05 then you have a significant difference.
I hope that helps.
why is it not 35912/1000???
So if the chi-squared value is greater than the critical value, we reject the null hypothesis, but in statistical testing in maths, a result greater than the critical value means accepting the nulll hypothesis. Why is this different across the two subjects?