Petroleum pollution in oceans is known to increase the growth of a certain bacteria. Brian did a project for his ecology class in which he made a bacteria count (per 100 milliliters) in nine random samples of sea water. His counts gave the following readings: 17, 23, 18, 19, 21, 16, 15, 18, 21

a) Find the range.
b) Find the mean.
b) Find the median.

Find the mean and median of the set {3, 5, 1, 0, 5, 9, 12, 1, 3, 6, 2, 0, 4}

Find the percent increase of the number of sales of a small airline between the years 1997 and 2001 if the number of sales in 1997 were $550 million and in 2001 they were $780 million.

Evaluate: | 4 ? 9 |

Evaluate: (-2) * | -3 | / | 2 | * | -1 |

Evaluate: (-3) * (-4)2 ? 9 / (-3)

Evaluate: -62 ? (-4) 2