Chi~square Test Monohybrid Cross Dihybrid Cross Sex~linked Cross

Chi~square Test
monohybrid, dihybrid & sex-linked
FYI ~ How Do You Say Chi!Square!
• The following illustration will give you the
correct pronunciation! It's like the beginning of
KITE.
Monohybrid Cross
Practice Problem #1: F2 Results
Male Female
wild eyed 46 51
sepia eyed 16 15
• http://www.wadsworth.com/psychology_d/templates/student_resources/workshops/
stat_workshp/chi_sqr/chi_sqr_02.html
Dihybrid Cross
Practice Problem #2: F2 Results
Male Female
wild eyed/normal wing 63 66
sepia eyed/normal wing 19 21
wild eyed/vestigial wing 20 20
Sex~linked Cross
Practice Problem #3: F2 Results
Male Female
white eyed 31 29
wild eyed 28 32
sepia eyed/vestigial
wing
7 8

To solve problem: example for #1
Problem #1:
1. Total # of flies observed:
2. Observed Flies:
• wild eyes:
• sepia eyes:
3. Expected Flies:
4. Expected ratio:
• wild eyes:
• sepia eyes:
5. X 2 = (show all work)
6. V=
7. confidence =
To solve problem: example for #2
Problem #2:
1. Total # of flies observed:
2. Observed Flies:
• wild eyed/normal wings
• sepia eyed/normal wing
• wild eyed/vestigial wing
• sepia eyed/vestigial wing
3. Expected ratio:
4. Expected Flies:
• wild eyed/normal wings
• sepia eyed/normal wing
• wild eyed/vestigial wing
• sepia eyed/vestigial wing
5. X 2 = (show all work)
6. V=
7. confidence =
To solve problem: example for #3
Problem #3:
1. Total # of flies observed:
2. Observed Flies:
• wild eye female
• white eye female
• wild eye male
• white eye male
3. Expected ratio:
4. Expected Flies:
• wild eye female
• white eye female
• wild eye male
• white eye male
5. X 2 = (show all work)
6. V=
7. confidence =
X 2 = S (O - E) 2 / E