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. Invertebrate community at a meadow consists of 1200 fies, 200 buterfies, 650 bees and 200
snails. Lizard food preference for these groups of invertebrates is investgated in a research project.
41 fies, 5 buterfies, 30 bees and 2 snails are identted as lizard prey. Do the lizards show any
preference for these types of prey?
4. What is the type I error probability corresponding to χ2
= 5.04 and df = 3
5. 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 levels at 8 degrees of freedom?
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. You are a insurance agent running business in car insurance. There is 12000 blue, 5600 red, 1300
yellow and 8700 black car registered in your region. The accident report indicates that 324 blue,
120 red, 20 yellow and 298 black cars were involved in accidents over past 5 years. Would you
consider car color as a signitcant predictor of car accident?
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 red- and white-fowering peas.
First he crossed a red fowering dominant homozygote with a white-fowering recessive
homozygote. All the ofspring were red fowering heterozygotes. Of these he selected two and
crossed them again. The ofspring consisted of 390 red-fowering plants and 103 white-fowering
plants. Is this results signitcantly diferent from the expected 3:1 rato?
D. Sex rato 1:1 is expected in mammals. Female-biased 6:4 rato is observed in squirells. Is that
signitcantly diferent from 1:1 if observed on a sample of 10, 100 and 1000?
E. Colour of fruits of fruits achenes) in sunfower is a genetcally determined trait based on two
co-dominant 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 black-achened plants, 61 grey-achened plants and 25 whitshachened
plants. Do these counts signitcanctly difer from the 1:2:1 rato expected on the basis of
the Mendelian rules?