Question

Please provide details for this problem. I got 3.24; therefore accept the null hypothesis.

Answer 1

Answer:

See the answer below

Explanation:

The Chi-square ($X^2$) is calculated by the formula:

$X^2$ = $\frac{(O - E)^2}{E}$ where O = observed frequency and E = expected frequency

A standard dihybrid cross is expected to give 9:3:3:1 phenotypic ratio.

Phenotype               O                  E                                  $X^2$

Round yellow          104       9/16 x 160 = 90          $\frac{(104 - 90)^2}{90}$ = 2.18

Round green            27        3/16 x 160 = 30           $\frac{(27 - 30)^2}{30}$ = 0.30

wringled yellow         27        3/16 x 160 = 30           $\frac{(27 - 30)^2}{30}$ = 0.30

wrinkled green          2          1/16 x 160 = 10              $\frac{(2 - 10)^2}{10}$ = 6.40

Total  $X^2$ value to two decimal places = 9.18

Degree of freedom = (n-1) = 4 -1 = 3

Critical  $X^2$ value at 95% probabillity level = 7.815

Since the calculated  $X^2$ si more than the critical  $X^2$ value, the null hypothesis is rejected.