A dihybrid testcross is made to determine if genes C and D a…

A dihybrid testcross is made to determine if genes C and D are linked. The results are shown in the table.    Calculate Chi-square value and determine whether genes C and D are linked. Which of the following statements is correct?  Refer to Chi-square table below. 

In Drosophila, yellow bodies (y ) and white eyes (w ) are bo…

In Drosophila, yellow bodies (y ) and white eyes (w ) are both caused by recessive X-linked alleles. The normal alleles (y+ amd w+ ) cause tan bodies and red eyes, respectively. A y w female is mated to a y+ w+ male and the F1 progeny are allowed to mate with each other. Two hundred F2 were observed and they are: 55 y w; 45 y w+; 45 y+ w; 55 y+ w+.  What is the chi-square value for the test for goodness of fit of the null hypothesis of no linkage? (Recall that the chi-square statistic is the sum, for all classes, of (O-E)2/E.)