I know this is biology, but no one answered me in the biology forum, and cos the Chi square test is also part of Maths, I thought I might hopefully get some responses here.
An experiment was carried out to investigate the inheritance of grain shapes and colour in maize. The number of each type of grain on a cob were counted (observed number).
The results are shown in the table below:
it was predicted that the phenotype would be in the ratio 9 : 3 : 3: 1 and a chi-squared test was used to investigate whether there was a significant difference between the observed results and the expected results.
Complete the table by calculating the expected number (E) of grains of each phenotype.
So what I did was:
the ratio is 9 : 3 : 3 : 1
For yellow & smooth: 9/16 x 53 = 29.8125
Yellow & wrinkled: 3/16 x 20 = 3.75
and so on ...
but my answers are all wrong?? Where did I go wrong and what's the correct way to calculate the expected value?
Please help!! How do I CALCULATE the expected value? Chi square test!!
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- 16-04-2016 16:56
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- 16-04-2016 17:04
But you want to multiply the expected ratio (i.e. 9/16) by the TOTAL count (53 + 20 + 17 + 10 = 100)
So they should be:
yellow/smooth: 9/16 * 100 = 56.25
yellow/wrinkled: 3/16 * 100 = 18.75
white/smooth: 3/16 * 100 = 18.75
white/wrinkled: 1/16 * 100 = 6.25
You can see that these are much closer to the observed values.
I'm sure you can fill out the last column yourself from thatPost rating:2
- 16-04-2016 17:39
- 16-04-2016 17:45
- 16-04-2016 18:09
- 16-04-2016 18:10
- 16-04-2016 18:12
- 16-04-2016 18:15