In: Statistics and Probability
A scientist claims that pneumonia causes weight loss in mice. The table shows the weights (in grams) of six mice before infection and two days after infection. At
alphaαequals=0.050.05,
is there enough evidence to support the scientist's claim? Assume the samples are random and dependent, and the population is normally distributed. Complete parts (a) through (e) below.
Mouse |
1 |
2 |
3 |
4 |
5 |
6 |
|
---|---|---|---|---|---|---|---|
Weight (before) |
22.622.6 |
19.519.5 |
22.622.6 |
23.423.4 |
21.921.9 |
22.622.6 |
|
Weight (after) |
22.522.5 |
19.619.6 |
22.522.5 |
23.323.3 |
21.921.9 |
22.522.5 |
The table given below ,
Mouse | Weight (before) (X) | Weight (after)(Y) | di=X-Y | di^2 |
1 | 22.6 | 22.5 | 0.1 | 0.01 |
2 | 19.5 | 19.6 | -0.1 | 0.01 |
3 | 22.6 | 22.5 | 0.1 | 0.01 |
4 | 23.4 | 23.3 | 0.1 | 0.01 |
5 | 21.9 | 21.9 | 0 | 0 |
6 | 22.6 | 22.5 | 0.1 | 0.01 |
From table ,
Let ,
Hypothesis : VS (Claim)
The test statistic is ,
The critical value is ,
; From Excel "=TINV(2*0.05,5)"
Decision : Here , the value of the test statistic does not lies in the rejection region
Therefore , fail to reject the null hypothesis.
Conclusion : Hence , there is not sufficient evidence to support the scientist claim that the pneumonia causes weight loss in mice.