Which of the following statements about statistical concepts is FALSE（）

A. A frequency is a tabular display of data summarized into a relatively small number of intervals.

B. An interval is a set of return values within which an observation not falls.

C. A parameter is an descriptive measure of a population characteristic.

患者，女性，56岁，身高155厘米，体重60千克，因慢性胆囊炎发作入院，拟行腹腔镜下摘除胆囊，术前查Hb96g/L，PLT34×10⁹/L。

患者输注浓缩血小板20单位，每单位含血小板2×10¹⁰个，1小时后复查血小板84×10⁹/L，则血小板计数增高指数CCI为（）。

A.2.1

B.8.4

C.12.5

D.21.2

E.25.0