In attempting to control the strength of the wastes discharged into a nearby river, a paper firm has taken a number of measures. Members of the firm believe that they have reduced the oxygen-consuming power of their wastes from a previous mean of 500. There 25 readings had a mean of 308.8 and a standard deviation of 115.15. Does this sample provide evidence that they have reduced their wastes?

.

Step-by-step explanation:

e.

step-by-step explanation:

because there are always 10 numbers in a phone number.

let x be the money she spent so that she can earn the free t-shirt.

since, she already spent $112.49

⇒

also, as per the statement: jennifer must spend $250 or more in order to qualify for a free t-shirt at the store.

then,

we have an inequality i.,e

subtract 112.49 from both sides we get;

therefore, $137. 51 more money does jennifer need to spend so that she can earn the free t-shirt