Help with what you can please!

Show your work if you can!

Thank you!

Find the sum of the first 8 terms of the following sequence. round to the nearest hundredth if necessary.

The brain volumes (cm cubed) of 50 brains vary from a low of 904 cm cubed to a high of 1488 cm cubed. use the range rule of thumb to estimate the standard deviation s and compare the result to the exact standard deviation of 175.5 cm cubed, assuming the estimate is accurate if it is within 15 cm cubed

In 2014, the three largest economies in the world were (listed in order, from largest): a) the u. s., china, germany. b) the u. s., china, japan. c) china, the u. s., japan. d) china, the u. s., germany.