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The ticket sales for a current movie often depend on the rating, out of 5 stars, that the movie receives on a popular review website. The ratings for a movie from a random sample of moviegoers are shown in the table below.

\begin{tabular}{|l|l|l|l|l|}
\hline
2 & 5 & 4 & 3 & 3 \\
\hline
3 & 1 & 3 & 2 & 1 \\
\hline
2 & 4 & 3 & 3 & 4 \\
\hline
4 & 4 & 5 & 5 & 4 \\
\hline
\end{tabular}

What is the sample mean? What proportion of moviegoers in the sample gave a rating higher than the sample mean?

The sample mean is [tex]\square[/tex]

The proportion of moviegoers in the sample who gave a rating higher than the sample mean is [tex]\square[/tex]


Sagot :

To solve the given problem, we need to determine two things: the sample mean of the ratings and the proportion of ratings that are higher than the sample mean.

1. Calculate the Sample Mean:
- First, list all the ratings from the table:
[tex]\[ 2, 5, 4, 3, 3, 3, 1, 3, 2, 1, 2, 4, 3, 3, 4, 4, 4, 5, 5, 4 \][/tex]
- Next, sum these ratings:
[tex]\[ 2 + 5 + 4 + 3 + 3 + 3 + 1 + 3 + 2 + 1 + 2 + 4 + 3 + 3 + 4 + 4 + 4 + 5 + 5 + 4 = 64 \][/tex]
- There are 20 ratings in total.
- The sample mean is calculated by dividing the sum by the number of ratings, which is:
[tex]\[ \text{Sample Mean} = \frac{64}{20} = 3.25 \][/tex]

2. Determine the Proportion of Ratings Higher than the Sample Mean:
- Now we need to count how many ratings are higher than the sample mean (3.25).
- The ratings higher than 3.25 from the list are: 5, 4, 4, 4, 4, 5, 5, 4. There are 9 such ratings.
- To find the proportion, divide the number of ratings higher than the sample mean by the total number of ratings:
[tex]\[ \text{Proportion Higher} = \frac{9}{20} = 0.45 \][/tex]

Based on the calculations, the answers are as follows:

The sample mean is [tex]\( \boxed{3.25} \)[/tex].

The proportion of moviegoers in the sample who gave a rating higher than the sample mean is [tex]\( \boxed{0.45} \)[/tex].