What is the standard deviation if a proportion of 0.89 of nonconforming items is found from twelve samples of size 136, twelve samples of size 124, and thirty samples of size 131?

Consumer preferences for alternative product concepts can be measured through ________, a method for deriving the utility values that consumers attach to varying levels of a product's attributes

A) concept testing B) perceptual mapping C) gap level analysis D) conjoint analysis E) morphological analysis

Which of the following symbols represents the change or manipulation of the independent variable?

A) O B) X C) C D) I E) M