This is to be measured against that level of supervision which the nature of the work requires. In the operation of petitioner's business there are signs of a lack of control. Installers work at their own convenience, can refuse a particular installation job, and are generally left unsupervised. No time sheets are required, and installers are responsible to correct their own installation problems. On the other hand, all materials used in the installation process are furnished by petitioner.
Customers buy the installation service from petitioner and direct their complaints to it.
Payment for installation is made to petitioner who, in turn, pays the installer. Although petitioner does not regularly supervise the details of installation, the work of new installers is inspected, as there is no lack of expertise on the part of Mr. Wagoner. Most of the covering products which petitioner sells are also installed through it. The sale of floor and wall coverings and installation are therefore tied closely together. Installation has become a necessary part of petitioner's business and has therefore has become a part of the usual course of its business.