Average Monthly Temperature The average monthly temperature (in ${ }^{\circ} \mathrm{F}$ ) in Seattle, Washington, is shown in the table.
$$
\begin{array}{c|c||c|c}
\text { Month } & \text { 'F } & \text { Month } & \text { 'F } \\
\hline \text { Jan } & 42 & \text { July } & 66 \\
\hline \text { Feb } & 43 & \text { Aug } & 66 \\
\hline \text { Mar } & 47 & \text { Sept } & 61 \\
\hline \text { Apr } & 50 & \text { Oct } & 53 \\
\hline \text { May } & 56 & \text { Nov } & 45 \\
\hline \text { June } & 61 & \text { Dec } & 41
\end{array}
$$
(a) Plot the average monthly temperature over a two-year period, letting $x=1$ correspond to January of the first year. Do the data seem to indicate a translated sine graph?
(b) The highest average monthly temperature is $66^{\circ} \mathrm{F},$ and the lowest average monthly temperature is $41^{\circ} \mathrm{F}$. Their average is $53.5^{\circ} \mathrm{F}$. Graph the data together with the line $y=53.5 .$ What does this line represent with regard to temperature in Seattle?
(c) Approximate the amplitude, period, and phase shift of the translated sine wave.
(d) Determine a function of the form $f(x)=a \sin [b(x-d)]+c,$ where $a, b, c,$ and $d$ are constants, that models the data.
(e) Graph $f$ together with the data on the same coordinate axes. How well does $f$ model the given data?
(f) Use the sine regression capability of a graphing calculator to find the equation of a sine curve that fits these data (over a two-year interval).