Let the require value be x, then
P(z > x) = 0.025
1 - P(z < x) = 0.025
P(z < x) = 1 - 0.025 = 0.975
P(z < x) = P(z < 1.96)
x = 1.96
Therefore, <span>the positive critical value that corresponds to a right tail area of 0.025</span> is 1.96
The y-intercept of the line is 40
Well lets see. if you're being specific about the rigor, then the period means that <span>cos(2Π÷3(x+α))=cos(2Π÷3(x))</span>Therefore this gives <span>2π÷3α=2π</span>so α = 3.
Hope this can help you