For the first question , why when the humidity increase by 1 percent , the moisture content will increase by 0.2727 percent ? Shouldn't it the moisture content will increase by 0.2727 + 0.4911 percent when the humidity increase by 1 percent ???

Second question , it's clear that in the 2nd photo , the slope , B_1 is 0.2724. It's is to test whether the slope equal to 1 in example 5 .. Why at the end of result , we should do not reject H0 , and conclude that B_1 is 1 ?

P/s : Example 5 (3rd and 4th photo) is continuous from example 3 (first and second photo)

I think for the second question is wrong . It's clear that in example 3 the B_1 is 0.2724 , which is not 1 . So , i think we should reject H0 , so that the slope , B_1 not equal to 1 . Correct me if i am wrong .