Homework Assignment #3

Questions

1. Let a = 0.05 and test Ho: Factors A and B are independent. Use the contingency X test and the short formula to test Ho. Then calculate the expected frequency for each class and use
   
   X = S(|O-E| - 1/2)      to test Ho.
                  E
   
   A cross Rr x Rr was made in both 1997 and 1998. Factor A is the genetic segregation and factor B is the year. The F progeny are expected to segregate in a 3:1 ratio each year.

Interpret the results of the X test.

1.  
2. Four plants were testcrossed. Each testcross was the result of crossing an F plant to a homozygous tester. The testcross can be represented using the symbols Rr x rr Rr:rr. Use the heterogeneity X to determine whether the same segregation ratio was observed for each of the four plants. Interpret the results. The following data was observed.

				X	df
1	O	27	22
	E	24.5	24.5
	(O-E)	0.255	0.255	0.510	1
	E
2	0	40	45
	E	42.5	42.5
	(O-E)	0.147	0.147	0.294	1
	E
3	O	51	48
	E	49.5	49.5
	(O-E)	0.045	0.045	0.090	1
	E
4	O	15	16
	E	15.5	15.5
	(O-E)	0.016	0.016	0.032	1
	E			0.926	4

Total	O	133	131
	E	132	132
	(O-E)	0.008	0.008	X = 0.016 accept Ho:1:1
	E

	X	df
Total	0.016	1
Summed	0.926	4
Het.	0.91	3	accept Ho: homogenous data