Recently, the manager of the call center for a large Internet bank asked his staff to collect data on a random sample of the bank’s customers. Data on the following variables were collected and placed in a file called Bank Call Center:

A small portion of the data is as follows:

a. Would you classify these data as time-series or cross-sectional? Explain.
b. Which of the variables are quantitative and which are qualitative?
c. For each of the six variables, indicate the level of data measurement.