/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 12 The candy company claims that \(... [FREE SOLUTION] | 91Ó°ÊÓ

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The candy company claims that \(16 \%\) of the Milk Chocolate M\&M's it produces are green. Suppose that the candies are thoroughly mixed and then packaged in small bags containing about \(50 \mathrm{M} \& \mathrm{M}^{\prime} \mathrm{s}\). A class of elementary school students learning about percents opens several bags, counts the various colors of the candies, and calculates the proportion that are green. a) If we plot a histogram showing the proportions of green candies in the various bags, what shape would you expect it to have? b) Can that histogram be approximated by a Normal model? Explain. c) Where should the center of the histogram be? d) What should the standard deviation of the sampling distribution be?

Short Answer

Expert verified
a) Approximately normal, b) Yes, meets normal conditions, c) Center at 0.16, d) Standard deviation is about 0.051.

Step by step solution

01

Interpret the Problem

We are looking at the distribution of the proportion of green M&M's in bags of 50 candies. Given that the company claims 16% of their M&Ms are green, we have a sample proportion problem.
02

Apply CLT for Proportions

The Central Limit Theorem (CLT) suggests that the sampling distribution of the sample proportion can be approximated by a Normal distribution if certain conditions are met: random samples, independence, large enough sample size, and np & nq ≥ 10.
03

Shape of the Histogram

a) The shape of the histogram of sample proportions should be approximately normal, given a sufficiently large sample size.
04

Check Normal Model Condition

b) We can use a Normal model if np and nq are both greater than 10. Here, n = 50, p = 0.16, so np = 50*0.16 = 8 and nq = 50*0.84 = 42, thus barely satisfying the Normal approximation conditions.
05

Determine the Center

c) The center of the histogram should be around the mean of the sample proportion, which is equal to the population proportion (p = 0.16).
06

Calculate the Standard Deviation

d) The standard deviation of the sampling distribution of the proportion is given by \( \sigma_{\hat{p}} = \sqrt{\frac{p(1-p)}{n}} = \sqrt{\frac{0.16 \cdot 0.84}{50}} \approx 0.051 \) (rounded).

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Key Concepts

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

Normal distribution
The concept of a normal distribution is fundamental in statistics. It refers to a symmetrical, bell-shaped curve used to represent the distribution of many types of data. In a perfect normal distribution, most of the data points cluster around the mean, and the probability of data points decreases as one moves away from the mean. This results in the characteristic bell shape.
For the distribution of the proportion of green M&M's from different bags, a normal distribution helps us predict outcomes. When we assume that the distribution of these proportions is approximately normal, we can make several inferences regarding their patterns and behaviors.
The normal distribution is particularly powerful because it allows us to use the properties of the curve to estimate probabilities and expectations, standard deviations, and other statistical measures. Therefore, if the conditions set by the Central Limit Theorem are met, we can confidently use a normal distribution to model our data.
Sampling distribution
The sampling distribution is a crucial concept when it comes to understanding how sample statistics can vary. It is essentially the probability distribution of a given statistic based on random sampling. In our problem, it refers to the distribution of the proportion of green M&M's when many bags are sampled.
Because we expect some variation across different samples, sampling helps us describe these variations and estimate the likely range of the population statistic. According to the Central Limit Theorem, when we have a large enough sample size and the samples are independent, the distribution of the sample proportions will be approximately normal.
In this exercise, even though the sample size of 50 is not very large, it is enough to start showing a pattern that can be approximated by a normal distribution. This helps us to predict and make conclusions about the entire population of M&M's, based on our sample data.
Proportions
Proportions are a way of expressing a part of a whole and are incredibly useful in statistics. In this exercise, the proportion refers to the number of green M&M's compared to the total number of M&M's in a bag. Since the company claims that 16% of M&M's are green, this forms our theoretical proportion value, denoted as "p".
In the context of sampling distributions, the proportion becomes a statistic called the sample proportion, denoted as "\(\hat{p}\)" (read as "p-hat"). This represents the observed ratio of green candies in each sampled bag.
Understanding proportions allows us to calculate various statistical measures, like the expected mean of the proportions and their standard deviation. This calculation involves using formulas to understand variations in our data set, helping us establish a range for normal behavior and identify outliers or unexpected patterns.
Histogram shape
A histogram is a visual representation of data distribution, using bars of different heights to show the frequency of data points within certain ranges. The shape of a histogram provides valuable insights into the nature of the data.
In our case, plotting a histogram for the proportions of green M&M's in different bags should yield an approximately normal shape. This means that most bags will have a proportion of green M&M's close to 16%, with fewer bags at the extremes having significantly higher or lower proportions.
It's crucial to consider the sample size and how the histogram shape might change with different sizes. In smaller samples, the histogram might appear slightly off from a perfect bell-shaped curve, but with larger samples, the approximation will become more accurate. This histogram is essential for understanding how well our sample data fits the expected normal distribution pattern.

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