Please use the bottom picture as a reference, I can't seem to get this question and I need help understanding and walking through it

an office visit when a same women were weighed again. of 1296 women who were part of the Kaiser Foundation the period 1961-1972.4 2 3 4 5 6 7 8 9 1 10 Subject: 112 119 130 115 151 137 162 116 130 121 Before: 130 153 118 After: 125 130 139 132 155 146 167 Subject: 11 12 13 14 15 16 17 18 19 20 Before: 112 140 136 129 115 102 138 133 118 185 After: 112 157 155 136 136 111 175 172 121 163 Test whether women gain weight in the 10 years after a pregnancy at the a = 5% level of significance. Solution Here we use the sign test, listing the six steps mentioned in the box above. Let 7 be the proportion of women in the population of NV = 1296 who increase in weight over the 10-year period. Step 1. Ho : The median weight has remained the same (7 = 0.5). Step 2. Ha : The median weight has increased (T > 0.5). Step 3. a = 0.05 Step 4. Because there is one tie, which is discarded, it leaves us with a sample of n = 19. There are 17 increases in weight, so 17 signs (+) and 2 signs (-). The test statistic is ks = 17. Step 5. The P-value is calculated using the 7 = 0.5 column of Table 2 for the group n = 19 on page 507. P-value = Pr(K _ Ks) = 1 - 0.9996 = 0.0004. Because P-value