Table of contents
- 1. Intro to Stats and Collecting Data24m
- 2. Describing Data with Tables and Graphs1h 55m
- 3. Describing Data Numerically53m
- 4. Probability1h 29m
- 5. Binomial Distribution & Discrete Random Variables1h 16m
- 6. Normal Distribution and Continuous Random Variables58m
- 7. Sampling Distributions & Confidence Intervals: Mean1h 3m
- 8. Sampling Distributions & Confidence Intervals: Proportion1h 5m
- 9. Hypothesis Testing for One Sample1h 1m
- 10. Hypothesis Testing for Two Samples2h 8m
- 11. Correlation48m
8. Sampling Distributions & Confidence Intervals: Proportion
Sampling Distribution of Sample Proportion
Problem 6.3.18b
Textbook Question
Hybridization A hybridization experiment begins with four peas having yellow pods and one pea having a green pod. Two of the peas are randomly selected with replacement from this population.
b. Find the mean of the sampling distribution.

1
Step 1: Understand the problem. The population consists of 4 yellow pod peas and 1 green pod pea. Since the selection is with replacement, the probability of selecting a yellow pod pea (P(Y)) is 4/5, and the probability of selecting a green pod pea (P(G)) is 1/5. The random variable X represents the number of green pod peas selected in two trials.
Step 2: Recognize that the random variable X follows a binomial distribution because there are a fixed number of trials (n = 2), each trial is independent, and there are only two outcomes (green or yellow). The probability of success (selecting a green pod pea) is p = 1/5.
Step 3: Recall the formula for the mean (expected value) of a binomial distribution: E(X) = n * p, where n is the number of trials and p is the probability of success.
Step 4: Substitute the values into the formula. Here, n = 2 (two selections) and p = 1/5 (probability of selecting a green pod pea). The formula becomes E(X) = 2 * (1/5).
Step 5: Simplify the expression to find the mean of the sampling distribution. The result will represent the expected number of green pod peas selected in two trials.

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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Sampling Distribution
A sampling distribution is the probability distribution of a statistic obtained by selecting random samples from a population. In this context, it refers to the distribution of the means of samples drawn from the population of peas with yellow and green pods. Understanding this concept is crucial for calculating the mean of the sampling distribution.
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Mean
The mean, or average, is a measure of central tendency that summarizes a set of values by dividing the sum of those values by the number of values. In the context of the sampling distribution, the mean represents the expected value of the sample means, which can be calculated based on the population proportions of yellow and green pods.
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Calculating the Mean
Random Sampling with Replacement
Random sampling with replacement means that each selected item is returned to the population before the next selection, allowing for the same item to be chosen multiple times. This method affects the probabilities of outcomes and is essential for determining the characteristics of the sampling distribution, including its mean.
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