Practicals 5. Goioidness oi st test
1. Colour preferences of bees were studied. The bees were released one by one to a room with 4
circles of diferent colours. The colour of circle to which each bee trst landed was recorded. The
results were following: red 10, yellow 25, blue 18, green 6. Do the bees prefer any colour?
2. The expected phenotype rato AB:Ab:aB:ab in the F2 generaton AABB x aabb) is 9:3:3:1. The
real numbers were as following: 125, 60, 50, 12. Are the ratos diferent from those expected under
Mendel rules?
3. What is the type I error probability corresponding to χ2
= 5.04 and df = 3
4. Which values of χ2
with 3 degrees of freedom is required for a signitcant test at α = 0.05 and α =
0.01. Which values of χ2
are required for the same signitcance level with 8 degrees of freedom?
5. Sex rato 1:1 is expected in mammals. Femalebbiased 6:4 rato is observed in squirells. Is that
signitcantly diferent from 1:1 if observed on a sample of 10, 100 and 1000?
6. In F1 generaton AA x aa) all individual were expected to display the dominant phenotype. 3
individuals of 2000 had the recessive phenotype. Is this result diferent from expectaton?
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A. Colour of fruits of fruits achenes) in sunfower is a genetcally determined trait based on two
cobdominant alleles. That is, dominant homozygotes have black achenes, recessive homozygots
whitsh achenes and heterozygots grey have achenes. In a crossing experiment performed, the F2
generaton of hybrids included 19 blackbachened plants, 61 greybachened plants and 25 whitshb
achened plants. Do these counts signitcanctly difer from the 1:2:1 rato expected on the basis of
the Mendelian rules?
B. 5 kinds of beer were available at a university music festval with contnuous supply so in a
theoretcally unlimited amount). Beer was served exclusively in 0.5 grasses and the price and the
speed of serving did not difer among the beers.
Numbers of glasses consumed are summarized for each beer in a table below:
Starobrno 12° 120
Starobrno 11° 180
Pilsner Urquell 150
Bernard 12° 320
Polička 11° 450
Is there any signitcant preference for some beers? Which beers are preferred? Which beer do you
prefer?
C. Johann Gregor Mendel performed crossing experiments with redb and whitebfowering peas.
First he crossed a red fowering dominant homozygote with a whitebfowering recessive
homozygote. All the ofspring were red fowering heterozygotes. Of these he selected two and
crossed them again. The ofspring consisted of 390 redbfowering plants and 103 whitebfowering
plants. Is this results signitcantly diferent from the expected 3:1 rato?