Standard error = sqrt(0.681^{2}/82+0.208^{2}/109) = 0.077798

z = (9.09-9.22) /0.077798 = -0.13/0.077798 = -1.67

| z | = 1.67

Since we are having two sided alternative, we will only take the magnitude and not the sign.

I am not sure whether they feed the answer as 1.67 or -1.67

That is why I am posting both the values.

Secure Information

Content will be erased after question is completed.

Enter the email address associated with your account, and we will email you a link to reset your password.

Forgot your password?

Sign Up