Flu Vaccine: The Center for Disease Control (CDC) claims that the flu vaccine is effective in reducing the probability of getting the flu. They conduct a trial on 3000 people. The results are summarized in the contingency table below.
Observed Frequencies: Oi's
Got | No | ||
Vaccine | Vaccine | Totals | |
Got Flu | 33 | 32 | 65 |
No Flu | 1917 | 1018 | 2935 |
Totals | 1950 | 1050 | 3000 |
The Test: Test for a dependent relationship between getting the vaccine and getting the flu. Conduct this test at the 0.01 significance level.
(a) What is the null hypothesis for this test?
H0: Getting the flu vaccine and getting the flu are dependent variables. H0: Getting the flu vaccine and getting the flu are independent variables. H0: Getting the flu vaccine helps prevent the flu.
(b) What is the value of the test statistic? Round to 3
decimal places unless your software automatically rounds to 2
decimal places.
χ2
=
(c) Use software to get the P-value of the test statistic.
Round to 4 decimal places unless your software
automatically rounds to 3 decimal places.
P-value =
(d) What is the conclusion regarding the null hypothesis?
reject H0 fail to reject H0
(e) Choose the appropriate concluding statement.
We have proven that getting the flu vaccine prevents the flu. The evidence suggests that getting the flu vaccine and getting the flu are dependent variables. There is not enough evidence to conclude that getting the flu vaccine and getting the flu are dependent variables.
(a)
Correct option:
H0: Getting the flu vaccine and getting the flu are independent variables.
(b)
Expected Frequencies are got as follows:
Got vaccine | No vaccine | Total | |
Got flu | 1950X65/3000=42.2500 | 1050X65/3000=22.7500 | 65 |
No flu | 1950X2935/3000=1907.7500 | 1050X2935/3000=1027.2500 | 2935 |
Total | 1950 | 1050 | 3000 |
Test Statistic is
calculated as follows:
Observed (O) | Expected (E) | (O - E)2/E |
33 | 42.2500 | 2.0251 |
32 | 22.7500 | 3.7610 |
1917 | 1907.7500 | 0.0448 |
1018 | 1027.2500 | 0.0833 |
Total = ![]() |
5.914 |
(c)
ndf = (r - 1) X (c - 1)
= (2 - 1) X (2 - 1)
= 1
By Technology, P - value = 0.0150
(d)
Correct option:
fail to reject H0
(e)
Correct option:
There is not enough evidence to conclude that getting the flu vaccine and getting the flu are dependent variables.
Get Answers For Free
Most questions answered within 1 hours.