A chemical company wishes to study the difference in response times (in milliseconds) for a number of different types of circuits used in an automatic value shutoff mechanism. From past studies, the value of e is taken to be 2 milliseconds. The researcher has a list of over 100 Types of Circuits that are of interest to the company. The company wants to determine if there is a significant variation in the performance of the 100 Types of circuits. In order to control for the variation within each Type of Circuit, she decides it is necessary to evaluate 5 circuits of each Type selected for the study. How many different Types of Circuits must be selected for use in the experiment in order to obtain an =.01 test having power of at least 0.90 whenever the standard deviation in the Types of circuits is greater than 2.1 milliseconds.