Ughhh !
science

where do subduction
zones often occur?

a. where an oceanic plate is movie toward a continental plate

b. where two oceanic plates are moving away from each other

c. where a continental plate is being split into two parts

d. where two continental plates are colliding

The chemical composition of soil varies with depth. an article in communications in soil science and plant analysis describes chemical analyses of soil taken from a farm in western australia. fifty specimens were each taken at depths 50 and 250 cm. at a depth of 50 cm, the average no3 concentration (in mg/l) was 88.5 with a standard deviation of 49.4. at a depth of 250 cm, the average concentration was 110.6 with a standard deviation of 51.5. find a 95% confidence interval for the difference in no3 concentrations at the two depths.