A set of data containing the heights of ten students, in centimeters, of some students is shown below. [160, 169, 170, 179, 180, 189, 190, 199, 200, 209)
This set of data is represented by the following histogram:

Suppose there is a simple index of three stocks, stock abc, stock xyz, and stock qrs. stock abc opens on day 1 with 4000 shares at $3.15 per share. stock xyz opens on day 1 with 5000 shares at $4.30 per share. stock qrs opens on day 1 with 6000 shares at $4.60 per share. the price of stock abc on day 8 begins at $3.50. the price of stock xyz on day 8 begins at $3.90. stock qrs opens on day 8 with a price of $4.50 per share. assume that each stock has the same number of shares that it opened with on day 1. what is the rate of change of this simple index over 1 week?

What situation is an example of an observational study

If chord ab is congruent to chord cd, then what must be true about ef and eg?