Instruction 7.4 According to a Survey, Only 15% of Customers Who Visited

Short Answer

Instruction 7.4
According to a survey, only 15% of customers who visited the web site of a major retail store made a purchase. Random samples of size 50 are selected.
-Referring to Instruction 7.4,the standard deviation of all the sample proportions of customers who will make a purchase after visiting the web site is _________