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When Nevaeh goes bowling, her scores are normally distributed with a mean of 165 and a
standard deviation of 13. Out of the
90 games that she bowled last year, how many of them
would she be expected to score less
than 193, to the nearest whole number?
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Sagot :

Sure! Let's solve this step-by-step.

### Step-by-Step Solution

1. Understand the Given Values:
- The mean score [tex]\( (\mu) \)[/tex] is 165.
- The standard deviation [tex]\( (\sigma) \)[/tex] is 13.
- The total number of games [tex]\( (N) \)[/tex] is 90.
- The target score is 193.

2. Calculate the Z-Score:
- The Z-score formula is:
[tex]\[ Z = \frac{X - \mu}{\sigma} \][/tex]
- Plug in the values [tex]\( X = 193 \)[/tex], [tex]\( \mu = 165 \)[/tex], and [tex]\( \sigma = 13 \)[/tex]:
[tex]\[ Z = \frac{193 - 165}{13} = \frac{28}{13} \approx 2.15 \][/tex]

3. Find the Probability:
- We will use the cumulative distribution function (CDF) of the normal distribution to find the probability that a score is less than the Z-score calculated.
- The CDF value corresponding to a Z-score of approximately 2.15 is 0.9844 (rounded to four decimal places).

4. Calculate the Expected Number of Games:
- To find the expected number of games with a score less than 193, multiply the total number of games [tex]\( (N) \)[/tex] by the probability obtained:
[tex]\[ \text{Expected number of games} = N \times \text{Probability} = 90 \times 0.9844 \approx 88.59 \][/tex]

5. Round to the Nearest Whole Number:
- 88.59 rounded to the nearest whole number is 89.

### Conclusion
Out of the 90 games that Nevaeh bowled last year, she is expected to score less than 193 in approximately 89 of them.