The data is missing in the question. The data is provided below :
Document : 1     2      3      4      5     6      7      8 
Brand A       17  29    18    14    21   25    22    29
Brand B       21  38    15    19    22   30    31   37
Solution :
State of the hypothesis of the null hypothesis and alternate hypothesis.
Null hypothesis : 
Alternate hypothesis : 
These hypothesis is a one tailed test. The null hypothesis will get rejected when the mean difference between the sample means is very small.
Significance level = 0.05
Therefore the standard error is :  
                                                          = 3.602
And the degree of freedom, DF = 14

  = -1.319
Here,  = standard deviation of the sample 1
 = standard deviation of the sample 1
          = standard deviation of the sample 2
 = standard deviation of the sample 2
           = size of the sample 1
 = size of the sample 1
          = size of the sample 2
 = size of the sample 2 
           = mean of the sample 1
 = mean of the sample 1
          = mean of the sample 2
 = mean of the sample 2      
           d = the hypothesis difference between the population mean
The observed difference in a sample means t static of -1.32. From t distribution calculator to determine P( ) = 0.1042
) = 0.1042  
Since the P value of 0.1042 is greater than significance level o 0.05, we therefore cannot reject the null hypothesis. 
But from the test, we have no sufficient evidence that supports that Brand A is better than Brand B.