In: Statistics and Probability
Human blood is grouped into four types: A, B, AB and O. The percent of all Americans with each type of blood are as follows: O: 43%, A: 40% B: 12% and AB 5%. At a recent blood drive, the number of donors having different blood types are shown below:
O A B AB
60 65 15 10
1. The total sample size in this blood drive is: a. 125 b. 140 c. 150
2. The expected value (based on the information about the blood types for all Americans) of people having O type of blood in the blood-drive sample is: a. 60 b. 64.5 c. 67
3. The expected value (based on the information about the blood types for all Americans) of people having A type of blood in the blood-drive sample is: a. 60 b. 65 c. 67
4. The expected value (based on the information about the blood types for all Americans) of people having B type of blood in the blood-drive sample is: a. 10 b. 15 c. 18
5. The expected value (based on the information about the blood types for all Americans) of people having AB type of blood in the blood-drive sample is: a. 7.5 b. 10 c 15
6. The standardized test statistic value that is calculated by comparing the four observed values of the different blood types from the blood-drive sample with the four expected values is: a. 1.06 b. 2.06 c.3.06
7. The probability value of the event that the standardized test statistic would assume a value as large as that calculated in question 6 is: a. 0. 36 b. 0.46 c. 0.56
8. By comparing the probability value calculated in question 7 to a 5% level of significance in a hypothesis test we fail to reject the statement: a. There is no difference between the proportions of people having different blood types in the blood-drive sample and the proportions of all Americans having different blood types b. There is a positive difference between that the proportions of people having different blood types in the blood-drive sample and the proportions of all Americans having different blood types c. There is a negative difference between the proportions of people having different blood types in the blood-drive sample and the proportions of all Americans having different blood types.