The new larger data storage devices will be measured in terabytes 1 TB equals 1 * 10 ^ 12 bytes what is another name for this number

Aparticular telephone number is used to receive both voice calls and fax messages. suppose that 25% of the incoming calls involve fax messages, and consider a sample of 25 incoming calls. (a) what is the expected number of calls among the 25 that involve a fax message?