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Training Fish to Pick a Color Fish can be trained quite easily. With just seven days of training, golden shiner fish learn to pick a color (yellow or blue) to receive a treat, and the fish will swim to that color immediately. On the first day of training, however, it takes them some time. In the study described under Fish Democracies above, the mean time for the fish in the study to reach the yellow mark is \(\bar{x}=51\) seconds with a standard error for this statistic of 2.4 . Find and interpret a \(95 \%\) confidence interval for the mean time it takes a golden shiner fish to reach the yellow mark. Is it plausible that the average time it takes fish to find the mark is 60 seconds? Is it plausible that it is 55 seconds?

Short Answer

Expert verified
The 95% confidence interval for the mean time it takes a golden shiner fish to reach the yellow mark is \(46.296\) seconds to \(55.704\) seconds. It is plausible that the average time it takes fish to find the mark is 55 seconds. It is not plausible that this average time is 60 seconds.

Step by step solution

01

Calculate the 95% confidence interval

Using the given sample mean and standard error, we can calculate the 95% confidence interval using the formula \(\bar{x} \pm 1.96*(\mathit{standard} \, \mathit{error})\). Plugging in the values from the problem, we get: \(51 \pm 1.96*(2.4)\).
02

Solve for the confidence interval

Doing the calculation, we get: \(51 \pm 4.704\). This means the 95% confidence interval is \(46.296\) seconds to \(55.704\) seconds.
03

Evaluate the plausibility of the mean times

Now we can look at whether 60 seconds and 55 seconds fall within our confidence interval. The time of 55 seconds falls within the interval, but the time of 60 seconds does not. Therefore, it is plausible that the average time to find the mark could be 55 seconds, but 60 seconds is not plausible.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Statistical Analysis
Statistical analysis is a fundamental process in which data is collected, reviewed, and then analyzed to draw meaningful conclusions. In this context, statistical analysis helps us understand how certain factors influence the time it takes golden shiner fish to reach a color mark during training.

The core component of statistical analysis in this scenario is establishing a confidence interval around the sample mean. This helps us understand the range within which the true population mean is likely to lie. By analyzing this interval, we can make informed decisions about the training results.
  • We start with a sample mean, which is an average calculated from the observed data (here, it's 51 seconds).
  • Using additional metrics like standard error, we estimate the variability of our sample mean to represent the population mean accurately.
  • A 95% confidence interval is calculated, providing a range indicating where the true average could likely be, 95% of the time.
Using this interval, we evaluate plausible scenarios, questioning whether our observed sample can reasonably include an assumed population mean (such as 55 or 60 seconds). Thus, statistical analysis offers a structured approach to interpreting experimental data and gauging the reliability of the results.
Mean Calculation
Mean calculation is a basic statistic that involves finding the central value or average of a set of numbers. This is particularly useful in analyzing data from experiments or studies. In our example, the mean time taken by golden shiner fish to reach the yellow mark was given as 51 seconds. This figure represents the central tendency of times recorded during the study.

Calculating the mean is done by summing all the observed times and dividing by the number of observations. The formula can be written as: \[ \text{Mean} = \frac{\sum x}{n} \] Where \( \sum x \) represents the sum of all data points and \( n \) represents the number of observations.

The mean offers valuable insight because it gives a single, comprehensible figure that captures the essence of the dataset. Without such a measure, it would be hard to make sense of different individual times.
  • It helps in identifying how long, on average, the fish took to reach their target color.
  • Aids in constructing a confidence interval to further analyze the data's reliability and variational range.
The mean is, therefore, a cornerstone of statistical interpretation, allowing us to summarize and understand the data from experiments efficiently.
Standard Error
Standard error is an essential statistic that quantifies the variability of the sample mean from the true population mean. While the sample mean provides an estimate of the population mean, it is rarely exact. That's where the standard error helps—it measures the accuracy of the sample mean as an estimator.

The standard error is calculated using the formula: \[ \text{Standard Error (SE)} = \frac{\sigma}{\sqrt{n}} \] where \( \sigma \) is the sample standard deviation, and \( n \) is the sample size.

In our fish training scenario, the standard error was given as 2.4. This value suggests how much the sample mean of 51 seconds might vary if different samples were taken.
  • Helps in constructing confidence intervals: A smaller standard error indicates that the sample mean is closer to the true population mean.
  • Allows researchers to assess whether a sample mean is a good representation of the population mean.
The role of standard error is critical; it informs the precision of the sample mean, ensuring researchers and students understand the data's reliability. By grasping the concept of standard error, you gain more profound insight into statistical interpretations and the confidence intervals derived from them.

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