Suppose the proportion of sophomores at a particular college who purchased used textbooks in the past year is ps and the proportion of freshmen at the college who purchased used textbooks in the past year is pf . A study found a 98% confidence interval for ps - pf is (0.238, 0.424). Give an interpretation of this confidence interval.

no solution

step-by-step explanation:

there is not enough information in the problem to solve.

the solution of the equation is 2.23 ⇒ answer b

step-by-step explanation:

* lets revise the meaning of exponential function

- the form of the exponential function is y = ab^x, where a ≠ 0, b > 0 ,  

  b ≠ 1, and x is any real number

- it has a constant base b

- it has a variable exponent x

- to solve an exponential equation, take the log or ln of both sides,  

  and solve for the variable

* lets solve the problem

∵

- the base is 7 and the exponent is x

- insert ㏑ in both sides

∴

- use the rule

∴ x ㏑(7) = ㏑(77)

- to find x divide both sides by ㏑(7)

∴

* the solution of the equation is 2.23 to the nearest 2 decimal places

c. 1,233 miles