In: Statistics and Probability
Geneticists examined the distribution of seed coat color in
cultivated amaranth grains, Amaranthus caudatus. Crossing
black-seeded and pale-seeded A. caudatus populations gave the
following counts of black, brown, and pale seeds in the second
generation.
According to genetics laws, dominant epistasis should lead to 12/16 of all such seeds being black, 3/16 brown, and 1/16 pale. We want to test this theory at the 5% significance level. |
(a) | Find the value of the test statistic. |
(b) | Fiind the critical value. |
(c) |
What is the conclusion? |
options for c)
(A) We cannot conclude that the observed
frequencies contradict the theory
since the answer in (a) is less than or equal to the answer in (b).
(B) We conclude that the data is consistent with the theory
since
the answer in (a) is greater than the answer in (b). (C) We
conclude that the theory is true since the answer in (a)
is less than or equal to the answer in (b). (D) We conclude that
the observed frequencies contradict the theory
since the answer in (a) is less than or equal to the answer in (b).
(E) We cannot conclude that the observed
frequencies contradict the theory
since the answer is (a) is greater than the answer in (b). (F) We
conclude that the theory is true since the answer in (a)
is greater than the answer in (b). (G) We conclude that the
observed frequencies contradict the theory
since the answer in (a) is bigger than the answer in (b).
Computational table:
Colour | Oi | % | Ei | (Oi-Ei) | (Oi-Ei)^2 | (Oi-Ei)^2/Ei |
black | 328 | 0.75 | =0.75*432 = 324 | 4 | 16 | 0.049 |
brown | 75 | 0.1875 | = 0.1875*432 = 81 | -6 | 36 | 0.444 |
pale | 29 | 0.0625 | =0.0625*432 = 27 | 2 | 4 | 0.148 |
Total | 432 | 1 | 432 | 0.642 |
Test statistic:
Degrees of Freedom: k-1 = 3-1 = 2
Where, K = Number of Categories = 3
b)
Critical value: For = 0.05
C)
Test statistic < critical value, i.e 0.642 < 5.99, That is Fail toReject Ho at 5% level of significance.
ANSWER: A
(A) We cannot conclude that the observed frequencies contradict the theory. since the answer in (a) is less than or equal to the answer in (b)