Identify the level of measurement of the​ data, and explain what is wrong with the given calculation. In a set of​ data, alert levels are represented as 10 for low, 20 for medium, and 30 for high. The average​ (mean) of the 719 alert levels is 25.4. The data are at the ________ level of measurement.
A. Nominal
B. Ordinal
C. Ratio
D. Interval