A final exam in Seaturtle Research Studies has a mean of 78 and a standard deviation of 3. If 36 students are randomly selected, find the probability that the mean of their test scores less than 79. P(x < 79) = P(z < (Enter your answer as a percent accurate to 1 decimal place, do not enter the "%" sign). Shade: Left of a value Click and drag the arrows to adjust the values. -4 -3 -2 1 -1 0 1 2 3 4 -1.5
Continuous Probability Distributions
Probability distributions are of two types, which are continuous probability distributions and discrete probability distributions. A continuous probability distribution contains an infinite number of values. For example, if time is infinite: you could count from 0 to a trillion seconds, billion seconds, so on indefinitely. A discrete probability distribution consists of only a countable set of possible values.
Normal Distribution
Suppose we had to design a bathroom weighing scale, how would we decide what should be the range of the weighing machine? Would we take the highest recorded human weight in history and use that as the upper limit for our weighing scale? This may not be a great idea as the sensitivity of the scale would get reduced if the range is too large. At the same time, if we keep the upper limit too low, it may not be usable for a large percentage of the population!
![### Probability of Mean Test Scores Less Than 79 in Seaturtle Research Studies
A final exam in Seaturtle Research Studies has a mean of 78 and a standard deviation of 3. If 36 students are randomly selected, we aim to find the probability that the mean of their test scores is less than 79.
#### Question
Given:
- Mean (\(\mu\)) = 78
- Standard deviation (\(\sigma\)) = 3
- Number of students (n) = 36
Find the probability \(P(x < 79)\):
\[ P(x < 79) = P\left(z < \frac{79 - \mu}{\frac{\sigma}{\sqrt{n}}} \right) = \]
\[ P\left(z < \frac{79 - 78}{\frac{3}{\sqrt{36}}}\right) = P\left(z < \frac{1}{\frac{3}{6}}\right) = P(z < 2) \]
Illustrate and calculate this probability using the standard normal distribution:
#### Standard Normal Distribution Explanation
Below is a standard normal distribution graph used to visually illustrate the probability:
![Standard Normal Distribution](graph-url)
- **Shaded Area**: The region to the left of \(z = 2\) is shaded in blue.
- **Meaning**: The shaded area represents \(P(z < 2)\).
- The arrow indicates the z-score of -1.5 corresponding to the 79 marks based on the standard normal distribution.
#### Instructions
Enter your answer as a percentage accurate to 1 decimal place without the "%" sign.
\[ P(z < 2) = \]
Let's calculate the exact percentage and fill in the box:
\[ P(z < 2) \approx 97.7\% \]
Thus:
\[ P(x < 79) = 97.7 \]
Enter the value:
\[ \boxed{97.7} \]
Remember to use this calculator:
Shade: Left of a value: \(87.7\)
Click and drag the arrows to adjust the values to calculate the precise z-score related probabilities.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Ff21c709c-710e-425a-a9e1-f3b584be2fe0%2Fc5da6f19-7e3a-4ebf-a1d0-ce22606c288b%2Fivvgtke_processed.png&w=3840&q=75)
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