Ill increase. may the same, but the standard deviation will increase. the mean age will stay the same, but the standard deviation will decrease. 6. For the following density curve, the median is ) 3.50 2.00 c ) 1.50 d 0.50 7. Normal density curve has which of the following properties? a) It is symmetric. b) It has a peak centered above its mean. c) The spread of the curve is proportional to the standard deviation. d) All of the above 8. A survey asks 200 students how much the spent-on textbooks this semester. What would the distribution of these textbook expenditures tell you? a) Who the students were b) How the students were selected c) That the costs were measured in dollars d) How frequently the various expenditures occurred in the data set 9. Which one of the following is a FALSE statement about a standardized value (z-score)? a) It represents how many standard deviations an observation lies from the mean. b) It represents in which direction an observation lies from the mean. c) It is measured in the same units as the variable. d) It is calculated Z = (X - )/