The F2 generation from a dihybrid cross produced a total of 219 tall plants with purple flowers, 72 dwarf plants with purple flowers, 69 tall plants with pink flowers, and 31 dwarf plants with pink flowers.
1: please state your hypothesis and explain how you arrived at this prediction
2:
phenotype  observe  expected 
Purple, tall  
Purple, dwarf  
Pink, tall  
Pink, dwarf  
total number of plants in F2 generation  
3: What is the chisquare value between the observed and expected offspring from the F2 generation for this dihybrid cross? (2 mark) Please report your chisquare value with 3 decimal places .
(a) What is the degrees of freedom for this dihybrid cross? Blank 1 (1 mark)
(b) What is the probability associated with your calculated chisquare value for this dihybrid cross?
Blank 2 < P < Blank 3
HINT: Make sure you enter the numbers on the correct side of the less than (>) symbols.
1. Null hypothesis: The observed values are not deviating from the expected ratio i.e. 9:3:3:1.
2. Test staic:
Category 
purple tall 
purple dwart 
pink tall 
pink dwarf 
Total 
Observed values 
219 
72 
69 
31 
391 
Exptected Ratio 
9 
3 
3 
1 
16 
Exprected Values 
219.9375 
73.3125 
73.3125 
24.4375 

Deviation 
0.9375 
1.3125 
4.3125 
6.5625 

D^2 
0.878906 
1.722656 
18.59766 
43.06641 

D^2/E 
0.003996 
0.023497 
0.253676 
1.762308 
2.043478 
X^2 
2.043478 

Degrees of freedom 
4 
 
1 
3 
3: The chisquare value between the observed and expected offspring from the F2 generation = 2.043
(a) What is the degrees of freedom for this dihybrid cross? = 41 = 3
(b) What is the probability associated with your calculated chisquare value for this dihybrid cross? 7.82 at 3 DF and 0.05 probability.
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