Question

A study of platelet aggregation in feline cardiomyopathy reported the platelet counts for 16 healthy cats and 10 with cardiomyopathy. These counts are shown in the table below. Do the data provide evidence that the population mean platelet count for health cats differs from the population mean platelet count for cats with cardiomyopathy? Use a 0.05 significance level.

Healthy Cats	Cats with Cardiomyopathy
2.24	2.42
2.54	3.61
3.04	6.24
2.12	3.12
2.10	5.50
2.98	2.40
2.78	2.18
4.01	4.27
6.30	2.42
2.70	4.69
3.76
2.55
2.40
2.70
2.10
3.11

Answer 1

To test,

H₀ : The mean platelet count for healthy cats is equal to that of mean platelet count for cats with cardiomyopathy

H₁ : The mean platelet count for healthy cats is not equal to that of mean platelet count for cats with cardiomyopathy

Here, alpha = 0.05

We use a t test for independent samples here. We use Minitab for that purpose.

The output is as follows :

N Mean StDev SE Mean
Healthy cats 16 2.96 1.05 0.26
Cats with cardiomyopathy 10 3.68 1.44 0.45

Difference = μ (Healthy cats) - μ (Cats with cardiomyopathy)
Estimate for difference: -0.721
95% CI for difference: (-1.846, 0.405)
T-Test of difference = 0 (vs ≠): T-Value = -1.37 P-Value = 0.191 DF = 14
p-value = 0.191

Since p value is greater than alpha = 0.05, we fail to reject the null hypothesis. Hence, we conclude that the data does not provide evidence that the population mean platelet count for helathy cats differ from that of cats with cardiomyopathy.