20. A density curve (probability density function) is a curve (A) that is on or above the measurement axis (B) with total area under the curve and above the measurement axis is equal to one (C) describes the distribution of a continuous measurement (D) all of these 21. A density curve (probability density function) can be viewed as a continuous version of a (A) population proportion (B) sampling method (C) discrete measurement (D) all of these 22. A discrete measurement X has a(n) (A) countable (B) uncountable collection of possible values. 23. The distribution of a discrete measurement X is described by a (A) probability mass function (B) probability density function 24. A continuous measurement X has a(n) ___ collection of possible values. (A) countable (B) uncountable 25. The distribution of a continuous measurement X is described by a (A) probability mass function (B) probability density function