the mean number of travel days per year for salespeople employed by three hardware distributors needs to be estimated with a 0.98 degree of confidence. for a small pilot study, the mean was 150 days and the standard deviation was 14 days. if the population mean is estimated within three days, how many salespeople should be sampled?

How often do neap tides occur? a. about once a month b. about twice a month c. about once a year d. about twice a year

In the image, layer a is the topmost layer. layer c contains fossils from the precambrian era. layer b contains dinosaur fossils, and layer a contains fossils of mammals. which two statements are supported by this evidence? 1. mammals lived before the precambrian era. 2. dinosaurs and mammals existed in the precambrian era. 3. dinosaurs evolved after precambrian organisms. 4. precambrian organisms evolved after dinosaurs. 5. precambrian organisms were the first life-forms to become fossilized, according to this sample.

Afish fossil is found in a rock. a foot bone and tooth are found in an older layer of the same rock. what can scientists learn from the rock? a) the area changed from land to water. b) the area changed from water to land. c) the area has always been land. d) the area was once an ocean.