Question

Probability theory and the binomial expansion show that, were you to sample families consisting of four children 1/16 of these families would consist of 4 boys, 4/16 would consist of 3 boys and 1 girl, 6/16 would consist of 2 boys and 2 girls, 4/16 would consist of 1 boy and 3 girls, and 1/16 would consist of 4 girls. Do the data in the sample given in the next table approximate this expectation? Complete the table, calculate X², and answer the questions based on your calculations.

Family Sex Ratio	O	E	(O-E)	(O-E)2	(O-E)2/2
All Boys	235
3B:1G	898
2B:2G	1317
1B:3G	841
All girls	181
Total					X2 =

A. interpret this X² value, you have __________ degrees of freedom.

b. In this case do you accept/reject the hypothesis that these data approximate a dihybrid test cross ratio with independent assortment?a. In interpreting this X² value, you have _____ dregrees of freedom.

c. What is the probability that the deviations are due to chance alone?

D. Determine whether the overall ratio of boys to girls in the above data is consistent with the hypothesis of a 50:50 sex ratio. Remember that each family included in the table consists of four children; for example, 235 families consisted of 4 boys, 898 families consisted of 3 boys and 1 girl, and 1317 families consisted of 2 boys and 2 girls. Calculate X² for these data by completing the following table:

Sex	O	E	(O-E)	(O-E)2	(O-E)2/E
Male
Female
Total					X2 =

E. Accept/Reject ________; df=_____________; P=___________

F. Calculate the ratio of boys to girls; record here:

G. How have biologists explained sex ratio data such as those observed in this problem?

Please explain the steps...... Thanks

Answer 1