Il What is the name given to the special pen attached to this device?

Which of the following methods could be considered a “best practice” in terms of informing respondents how their answers to an on-line survey about personal information will be protected? respondents are informed that investigators will try to keep their participation confidential; however, confidentiality cannot be assured. respondents are informed that a research assistant will transfer all the research data to a password-protected computer that is not connected to the internet, via a usb flashdrive. the computer is located in a research team member’s office. the investigator uses the informed consent process to explain her institution’s method for guaranteeing absolute confidentiality of research data. the investigator uses the informed consent process to explain how respondent data will be transmitted from the website to his encrypted database without ever recording respondents’ ip addresses, but explains that on the internet confidentiality cannot be absolutely guaranteed.

Which demographic challenge is europe currently experiencing? a. an aging and decreasing population b. a baby boomc. an unequal distribution between males and females d. a large group of teenagers moving through the school system(i chose a but i'm unsure)

Suppose there is a relation r(a, b, c) with a b+-tree index with search keys (a, b).1. what is the worst-case cost of finding records satisfying 10 < a < 50 using this index, in terms of the number of records n1, retrieved and the height h of the tree? 2. what is the worst-case cost of finding records satisfying 10 < a < 50 and 5 < b < 10 using this index, in terms of the number of records n2 that satisfy this selection, as well as n1 and h defined above? 3. under what conditions on n1 and n2, would the index be an efficient way of finding records satisfying the condition from part (2)?