Question

4 What of the following would increase random measurement error? a. Using a sphygmomanometer that falls to 1mm Hg when the cuff is released b. Chatting with a colleague while collecting data C. Entering data for 8 hours having had only 2 hours sleep. d. A and B e B and C 22. Instrument validity refers to the extent to which a. an instrument measures what it was intended to measure b. an instrument measures the phenomena consistently c. extraneous variables have been controlled d. the instrument items measure the same phenomenon 23. Internal validity of a study can be threatened by all of the following EXCEPT a. history b. maturation c. selection d. congruence

Answer 1

21) e - B and C

Random errors is due to fluctuations around the value as a result of difficulty taking measurements .

22) a - an instrument measures what it was intended to measure

Instrument validity is the extent to which an instrument measures what it is supposed to.Validity is established by correlating the scores with similar instruments

23)d-congruence