In: Statistics and Probability
| countries | sample size | sample mean | sample standard deviation | 
| brazil | n1=20 | 3.464294243 | 1.955414704 | 
| russia | n2=20 | 0.555334519 | 
 0.275727133  | 
A) Test at 5% level individually if the mean percentage for each of the means is different from 10%.
B) Obtain a 95% confidence interval for the difference of means for the two countries.
C) Test an appropriate pair of hypotheses for the two means at 5% level of significance