Self Assessment Question # 2
for Lesson 10

by Dr Jamie Love © 2002 - 2005
Genetics Course

Here are the results of a dihybrid cross involving roses. There is no need to tell you their history other than to say they are the result of a proper dihybrid cross. The F2s produced had these phenotypes and in these numbers.
Red and tall = 30
White and tall = 65
Red and short = 83
White and short = 206
Use the chi-square to determine if these results are what you would expect for the dihybrid cross.
Note and warning! This will take you more time and effort than the other chi-square, in the first SAQ of this section, so take it one step at a time and be sure you remind yourself that there are now four categories. You might want to set this up as a neatly organized table to follow because it gets pretty complicated!
2 = [(O - E)2/E]

Degrees of Freedom 5 % Significance Levels
1
3.84
2
5.99
3
7.81
4
9.49

Don't give up. If you get confused take a break, go back to read the section about chi-square again, or review the workshop.

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Dr Jamie Love, the producer of these Genetics lessons, has written several self-study science courses specifically designed for home schoolers and other distance learners. These courses are "hypertextbooks" - delivered over the internet and read on your computer, just like web pages.
To organize and distribute these hypertextbooks, Jamie created Merlin's Science Academy - a (non-accredited) "virtual school". Merlin's Science Academy sells self-paced, self-learning hypertextbooks that teach Alchemy (actually, Chemistry ), Astronomy and Genetics in a fun and unique way.
Each course has computerized exams, unique features and a style best suited for teaching the subject.

Principles of Alchemy (Chemistry) is for younger students (up to highschool),
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However, every student is different and it would not be fair to generalize. So, visit Merlin's Science Academy where you can learn more about the courses, request free samples of each course (to download onto your computer) and enjoy the free online samples.

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