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Suppose that the true proportion of Americans who save at least 15% of there income is 0.11 . If p-hat is the sample proportion of Americans surveyed who save at least 15% of their income, from a sample of size 45 , find P(p-hat <0.08).

User Rcty
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Final answer:

The student's question pertains to finding the probability that the sample proportion is less than 0.08 given a true population proportion of 0.11 with a sample size of 45. This requires standardization and the use of a Z-distribution, but the provided 'Solution 9.17' information is for a different hypothesis testing scenario and is not directly applicable.

Step-by-step explanation:

The student is asking about the probability of obtaining a sample proportion less than 0.08 when the true population proportion is 0.11. This involves the use of the sampling distribution of the sample proportion to calculate the likelihood. With a sample size of 45, we can assume the sampling distribution of the sample proportion (p-hat) is approximately normal due to the Central Limit Theorem, provided the np and n(1-p) conditions are met.

To find P(p-hat < 0.08), we need to standardize the sample proportion and use the standard normal distribution (Z-distribution) to calculate the area under the curve to the left of the standardized value. However, the given information from 'Solution 9.17' is unrelated to this problem, as the hypothesis test set there is for a different scenario with a different null hypothesis. Our focus should be on the principles of the sampling distributions and probability calculation.

The calculation would involve the formula for the standard error of the proportion and the use of a Z-score to find the corresponding probability from a standard normal distribution table or software. We cannot perform the actual calculation without additional information on the standard deviation of the sample proportion, which is typically derived from the population proportion and sample size.

User Nedret Recep
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