In: Statistics and Probability
Below, 25 and 50 mg / ml doses of a drug were given to subjects with the same properties and small blood pressure values were measured. Are the effects of doses different? Find with the error of 5% (The distribution of the data you will use is normal, the samples are sufficient and the variances are homogeneous)
| 
 1  | 
 2  | 
 3  | 
 4  | 
 5  | 
 6  | 
 7  | 
 8  | 
 9  | 
|
| 
 25 mg/ml doses  | 
 7  | 
 8  | 
 6  | 
 6  | 
 8  | 
 9  | 
 5  | 
 6  | 
 8  | 
| 
 50 mg/ml doses  | 
 9  | 
 9  | 
 8  | 
 10  | 
 9  | 
 11  | 
 7  | 
 9  | 
Null hypothesis:
there is no difference n the lower blood pressure after administration of 25 mg/ ml and 50 mg/ml of the drug soluton
Alternate hypothesis:
there is difference n the lower blood pressure after administration of 25 mg/ ml and 50 mg/ml of the drug soluton
For 25mg/ml,
If we calculate the mean and variance of all the 9 sample:
mean = 7
Variance = 1.75
For 50mg/ml,
If we calculate the mean and variance of all the 9 sample:
mean = 9
Variance = 1.4285
Now for two sample t test
t = (mean of 50 mg/ml -mean of 25 mg/ml) / sqrt (sum of (variance /number of sample)
t = (9-7)/sqrt(1.75/9 + 1.4285/8)
t = 2/sqrt(0.1944+0.1785))
t =3.2746
If we look at the t table and measure the critical value at 0.05 for 15 (9+8-1-1) degree of freedom for two tail:
2.1319
So calcuated t value is higher than the critical value so we reject the null hypothesis and accpet the alternate hypothesis and can say that there is a difference in lower blood pressure between the 25mg/ml dose and 50 mg/ml dose
So there is a differnece in lower blood pressure for 25 mg/ml and 50 mg/ml dose at 95% CI