A company claims that 9 out of 10 doctors (i.e. 90%) recomme…

A company claims that 9 out of 10 doctors (i.e. 90%) recommend its brand of cough syrup to their patients. To test this claim against the alternative that the actual proportion is less than 90%, a random sample of 200 doctors was chosen which results in who indicate that they recommend this cough syrup. Find the standardized test statistic, z. Round to two decimal places.   Hint: Do not forget the sign on your answer!