Prior to the Start of the Season, It Was Expected

Prior to the start of the season, it was expected that audience proportions for the four major news networks would be CBS 18.6%, NBC 12.5%, ABC 28.9% and BBC 40%. A recent sample of homes yielded the following viewing audience data.
$\begin{array}{|l|r|}\hline & \begin{array}{c}\text { Observed } \\\text { frequenciesf }\end{array} \\\hline \text { CBS } & 400 \\\hline \text { NBC } & 230 \\\hline \mathrm{ABC} & 560 \\\hline \mathrm{BBC} & 810 \\\hline \text { Total } & 2000 \\\hline\end{array}$ We want to determine whether or not the recent sample supports the expectations for the number of homes of the viewing audience of the four networks.
a. State the null and alternative hypotheses to be tested.
b. Compute the test statistic.
c. The null hypothesis is to be tested at 95% confidence. Determine the critical value for this test.
d. What do you conclude?