Math Problem Statement
Solution
From the image you provided, it appears you are working on a statistics problem related to sampling distributions. Let's break it down step by step.
Problem Overview:
-
Scenario:
- 37% of adults do not own a credit card.
- A simple random sample of 600 adults is obtained.
-
Questions:
- (a) Find the standard deviation of the sampling distribution of the sample proportion .
- (b) Find the probability that more than 41% of the sample do not own a credit card.
- (c) Interpret the probability from part (b) and estimate the expected number of samples where more than 41% do not own a credit card in 100 random samples.
Let's work through it:
Part (a): Standard Deviation of the Sampling Distribution of
The formula for the standard deviation (often called the standard error) of the sampling distribution of the sample proportion is:
Where:
- (the population proportion of adults who do not own a credit card),
- (the sample size).
Now, let's compute that:
I'll calculate that next.The standard deviation of the sampling distribution of is approximately 0.020 (rounded to three decimal places).
Part (b): Probability that more than 41% of the sample do not own a credit card
To find this probability, we first convert the proportion to a z-score using the formula:
Where:
- ,
- ,
- .
I'll calculate the z-score and then find the probability using the standard normal distribution.The z-score is approximately 2.03. Now, let's find the probability of getting a z-score greater than 2.03 using the standard normal distribution table (or a calculator). This corresponds to the area to the right of .
We can use a standard normal distribution to find this value.The probability that more than 41% of the sample do not own a credit card is approximately 0.0212 (or 2.12%).
Part (c): Interpretation and estimation for 100 random samples
Given that the probability is about 2.12%, we expect about 2.12% of the 100 random samples to result in more than 41% of adults not owning a credit card. To estimate this:
Rounding to the nearest integer, we expect about 2 samples.
Would you like further clarification or additional details on any part? Here are some related questions to explore:
- How would the standard deviation change if the sample size were increased?
- What does a z-score of 2.03 imply in terms of the distribution?
- What would be the probability if we asked about less than 41% of the sample not owning a credit card?
- How do we interpret the sampling distribution of proportions in real-world contexts?
- If the population proportion were different, how would that impact the probability calculation?
Tip: Always check the context of proportions in statistics, especially in large samples. Small changes can have a significant impact on the probabilities.
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Math Problem Analysis
Mathematical Concepts
Sampling distribution
Standard deviation
Proportions
Z-scores
Probability
Formulas
Standard deviation of the sample proportion: σ̂p = sqrt((p(1 - p)) / n)
Z-score formula: z = (p̂ - p) / σ̂p
Theorems
Central Limit Theorem
Suitable Grade Level
College level (Introductory statistics)
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