Use the given information to find the number degrees of freedom, critical values X 2/L and X 2/R and the confidence interval estimate of lower case sigma. It is reasonable to assume that a simple random sample has been selected from a population with a normal distribution. Platelet count in women 98% confidence; n=21, s=65.5 mg. Please show the break down of how to solve this type of problem along with calculator routine, if has one.

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