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Use the following information to answer the next 16 exercises: The Ice Chalet offers dozens of different beginning ice-skating classes. All of the class names are put into a bucket. The 5 P.M., Monday night, ages 8 to 12, beginning ice-skating class was picked. In that class were 64 girls and 16 boys. Suppose that we are interested in the true proportion of girls, ages 8 to 12, in all beginning ice-skating classes at the Ice Chalet. Assume that the children in the selected class are a random sample of the population. In words, define the random variable \(P^{\prime}\)

Short Answer

Expert verified
\(P^{\prime}\) is the proportion of girls in a sample of ice-skating classes.

Step by step solution

01

Understanding the Context

The Ice Chalet offers beginner ice-skating classes. In a randomly selected class, there are 64 girls and 16 boys. We aim to find the proportion of girls in this class and use it to make inferences about all similar classes.
02

Defining the Population Parameter

The population parameter we are interested in is the true proportion of girls in all beginning ice-skating classes that the Ice Chalet offers for ages 8 to 12.
03

Identifying the Sample Proportion

In the selected class, there are 64 girls out of a total of 80 students (64 girls + 16 boys). Hence, the sample proportion of girls, denoted as \(\hat{p}\), is calculated to be \(\frac{64}{80}\).
04

Defining the Random Variable

The random variable \(P^{\prime}\) represents the proportion of girls in a randomly selected sample of beginning ice-skating classes where each class has the same conditions as the selected class.
05

Writing the Definition in Words

\(P^{\prime}\) is the random variable that describes the proportion of girls aged 8 to 12 in a chosen sample of beginning ice-skating classes at the Ice Chalet.

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Key Concepts

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

Random Variable
A random variable is a fundamental concept in statistics. It represents a set of possible outcomes from a statistical experiment.
Think of it as a numerical summary of some aspect of a random process or sample. In our ice-skating class example, we are focusing on the random variable \( P^{\prime} \).
This random variable describes the proportion of girls in a randomly selected ice-skating class from the Ice Chalet.

Random variables can be either discrete or continuous. In our example, \( P^{\prime} \) is continuous because it represents a proportion that can take any value between 0 and 1.
  • Continuous random variables can assume an infinite number of values within a given range.
  • They are typically represented through a probability distribution.

Understanding \( P^{\prime} \) aids in estimating how likely certain proportions are by comparing them to the population parameter, thus ensuring that the sample accurately reflects the larger population of ice-skating classes.
Population Parameter
The population parameter is an essential concept when discussing sample statistics. It is the true value that describes some characteristic of a population.
In the context of our ice-skating classes, the population parameter of interest is the true proportion of girls aged 8 to 12 attending these classes.

This parameter is a fixed value, but it is usually unknown because it's impractical to examine every individual in a large population.
  • In our case, the entire population includes all beginning ice-skating classes for kids aged 8 to 12 at the Ice Chalet.
  • Researchers aim to estimate this parameter using data from a sample.

Using samples drawn from the population, like the one in our example (with 64 girls out of 80 students), we can make educated guesses about this population parameter. This process of inference allows statisticians and researchers to generalize findings from their sample to the broader population. By calculating the sample proportion, researchers can develop confidence intervals or conduct hypothesis tests to better understand how well the sample estimates the population parameter.
Ice-Skating Classes
Ice-skating classes provide an engaging and fun way for children to get exercise and develop new skills. The Ice Chalet offers various beginner ice-skating classes for kids aged 8 to 12.
This particular setting provides a great example for statistical analysis because it involves readily identifiable populations and samples.

Consider why ice-skating classes make a useful backdrop for learning about statistical concepts:
  • The classes are organized by specific age groups and times, allowing clear definition and sampling.
  • Since they involve multiple sessions, they provide repeated opportunities to measure variables like gender proportion.

These classes become an illustrative way to explore how sample statistics aim to reflect the true proportions found in a broader context. Understanding how to infer population characteristics based on class composition helps students grasp how statistical analysis can apply to real-world settings. This knowledge allows them to assess how representative their findings are of the larger group of ice-skating classes, and to improve decision-making processes related to teaching and structuring these courses. By evaluating gender proportions and other demographics, class organizers can ensure they meet the needs of all participants effectively.

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Most popular questions from this chapter

Use the following information to answer the next five exercises. Suppose the marketing company did do a survey. They randomly surveyed 200 households and found that in 120 of them, the woman made the majority of the purchasing decisions. We are interested in the population of households where women make the majority of the purchasing decisions. Construct a 95\(\%\) confidence interval for the population proportion of households women make the majority of the purchasing decisions. State the confidence interval, sketch the graph, and calculate the error bound.

Use the following information to answer the next seven exercises: The U.S. Census Bureau conducts a study to determine the time needed to complete the short form. The Bureau surveys 200 people. The sample mean is 8.2 minutes. There is a known standard deviation of 2.2 minutes. The population distribution is assumed to be normal. If the Census did another survey, kept the error bound the same, and surveyed only 50 people instead of 200, what would happen to the level of confidence? Why?

Use the following information to answer the next 14 exercises: The mean age for all Foothill College students for a recent Fall term was 33.2. The population standard deviation has been pretty consistent at 15. Suppose that twenty-five Winter students were randomly selected. The mean age for the sample was 30.4. We are interested in the true mean age for Winter Foothill College students. Let X = the age of a Winter Foothill College student. What is \(\overline{x}\) estimating?

Use the following information to answer the next seven exercises: The U.S. Census Bureau conducts a study to determine the time needed to complete the short form. The Bureau surveys 200 people. The sample mean is 8.2 minutes. There is a known standard deviation of 2.2 minutes. The population distribution is assumed to be normal. Construct a 90% confidence interval for the population mean time to complete the forms. State the confidence interval, sketch the graph, and calculate the error bound.

Use the following information to answer the next 16 exercises: The Ice Chalet offers dozens of different beginning ice-skating classes. All of the class names are put into a bucket. The 5 P.M., Monday night, ages 8 to 12, beginning ice-skating class was picked. In that class were 64 girls and 16 boys. Suppose that we are interested in the true proportion of girls, ages 8 to 12, in all beginning ice-skating classes at the Ice Chalet. Assume that the children in the selected class are a random sample of the population. State the estimated distribution of \(X . X \sim\) _____

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