A medical researcher hypothesizes that, within a particular ethnic group, the distribution of blood types is: 50% have type O, 25% have type A, 20% have type B, and 5% have type AB. He gathers blood type data for a random sample of 400 people from this ethnic group, and summarizes the observed counts in the following table. Suppose that a chi-square goodness of fit test is performed, and the null hypothesis is the researcher's hypothesis. What are the expected counts for blood types O, A, B, and AB, respectively?
A) 100, 100, 100, 100
B) 185, 106, 85, 24
C) 200, 100, 80, 20
D) 50, 25, 20, 5

Question

A medical researcher hypothesizes that, within a particular ethnic group, the distribution of blood types is: 50% have type O, 25% have type A, 20% have type B, and 5% have type AB. He gathers blood type data for a random sample of 400 people from this ethnic group, and summarizes the observed counts in the following table.  Suppose that a chi-square goodness of fit test is performed, and the null hypothesis is the researcher's hypothesis. What are the expected counts for blood types O, A, B, and AB, respectively?
A) 100, 100, 100, 100 
B) 185, 106, 85, 24 
C) 200, 100, 80, 20 
D) 50, 25, 20, 5

Quizplus · Accepted Answer

The Answer of A medical researcher hypothesizes that, within a particular ethnic group, the distribution of blood types is: 50% have type O, 25% have type A, 20% have type B, and 5% have type AB. He gathers blood type data for a random sample of 400 people from this ethnic group, and summarizes the observed counts in the following table.  Suppose that a chi-square goodness of fit test is performed, and the null hypothesis is the researcher's hypothesis. What are the expected counts for blood types O, A, B, and AB, respectively?
A) 100, 100, 100, 100 
B) 185, 106, 85, 24 
C) 200, 100, 80, 20 
D) 50, 25, 20, 5

A Medical Researcher Hypothesizes That, Within a Particular Ethnic Group