Fill in the missing words

62. When subjects who did not receive the real treatment but the imitation or placebo in an experiment, react as though they had received the actual treatment, this effect is known as the __________ ________ (3)

63. When the groups in an experiment are not equivalently selected, largely due to careless selection, this is called __________ ____ (3)

64. A survey question that contains more than one issue and can create confusion that lead to ambiguous answers is called a ______________ __________ (3)

65. A type of survey question where a respondent is free to offer any answer they wish to in a question, is known as an _____________________ (3)

66. A type of survey question where a respondent must choose from a fixed set of answers in known as a ________________________ (3)

67. Survey research make use of __________ and or ____________ to collect data from their research participants