A pollution control inspector suspected that a company that discharges its process water directly into a river was disch

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A pollution control inspector suspected that a company that
discharges its process water directly into a river was discharging
quantities of poorly treated water into the river. To test his
theory, he took five randomly selected river water samples from a
location upstream of the town, and another five from downstream.
The dissolved oxygen readings (in parts per million) are as
follows:
Upstream: 4.8 5.2 5.0 4.9 5.1
Downstream: 5.0 4.7 4.7 4.9 4.8 4.9 4.9
a.Do the data give sufficient evidence to indicate that the mean
oxygen content downstream of the village is less than the mean
oxygen content upstream?
b. What size will the samples need to be to identify differences
between the means of the two points at a value of at least 0.1
ppm?
c.How powerful would a test in which you want to test the null
hypothesis that the difference between the means is 0 be to
identify a difference between means of 0.1 ppm?
Step by step please