What is the difference between a bar chart and a histogram? a) there is no difference between these two graphical displays. b) the bars in a bar chart are all the same width while the bars of a histogram may be of various widths. c) the bars in a bar chart may be of various widths while the bars of a histogram are all the same width. d) the bars on a bar chart do not touch while the bars of a histogram do touch.

Suppose you are an ad-serving company and you maintain a log of cookie data for ads you serve to the web pages for a particular vendor (say amazon). a. how can you use this data to determine which are the best ads? b. how can you use this data to determine which are the best ad formats? c. how could you records of past ads and ad clicks to determine which ads to send to a given ip address? d. how could you use this data to determine how well the technique you used in your answer to part c was working? e. how could you use this data to determine that a given ip address is used by more than one person? f. how does having this data give you a competitive advantage vis-à-vis other ad-serving companies?