Question

Due to the increase in global travel and the prevalence of invasive species, the Anopheles mosquito carrying the malaria parasite was inadvertently introduced to this isolated Pacific island. A researcher, 100 years from the present day, decides to complete a follow-up study and monitors another 50 couples who are all heterozygous for type A blood and have sickle cell trait. These couples had 136 children. Based on the introduction of the Anopheles mosquito carrying the malaria parasite, predict scientifically logical observed numbers of children for each genotype possibility and complete a chi-square statistical analysis test.

i. What is your predicted chi-square value(x^2)?__________
ii. Calculate df. _______
iii. Using the critical values table, determine the predicted P value.

Answer 1

i. Predicted chi-square value(x^2)?______ 22.35

ii. df_______ 6-1= 5

iii. Using the critical values table, determine the predicted P value

The P-Value is .050985 for 5 df and 0.05 significance level. The result is not significant at p < .01.

The P-Value is .010362 for 5 df and 0.01 significance level. The result is not significant at p < .01.

Explanation:

Phenotype Predicted ( o) Expected (e) (o-e) (o-e)²/e

(observed)

A- normal 19 3/4 * (1/4)= 3/16 25.5 -6.5 1.66

O normal 5 1/4 * (1/4)= 1/16 8.5 -3.5 1.44

A trait 70 3/4 * (1/2)= 3/8 51 19 7.07

O trait 25 1/4 * (1/2)= 1/8 17 8 3.67

A Disease 13 3/4 * (1/4)= 3/16 25.5 -12.5 6.13

O Disease 4 1/4 * (1/4)= 1/16 8.5 -4.5 2.38

136 136 22.35

i. What is your predicted chi-square value(x^2)?______ 22.35

ii. Calculate df_______ 6-1= 5

iii. Using the critical values table, determine the predicted P value

The critical region for alpha =0.05 is χ² ≥ χ² (0.05,5) = 11.02

The P-Value is .050985. The result is not significant at p < .01.

The critical region for alpha =0.01 is χ² ≥ χ² (0.01,5) = 15.00

The P-Value is .010362. The result is not significant at p < .01.

The calculated value of chi square is 22.35 which is greater than 15.00 and 11.02 , the critical regions at alpha 0.05 and 0.01

Therefore it falls in the critical region and the result is insignificant.