Concept explainers
Interpret a confidence interval: A survey organization drew a simple random sample of 625 households from a city of 100,000 households. The sample
True or false, and explain:
- We are 95% confident that the mean number of people in the 625 households is between 2.16 and 2.44.
- We are 95% confident that the mean number of people in the 100,000 households is between 2.16 and 2.44.
- The
probability is 0.95 that the mean number of people in the 100,000 households is between 2.16 and 2.44. - 95% of the households in the sample contain between 2.16 and 2.44 people.
a.
To explain: Whether the statement “We are
Answer to Problem 64E
The given statement “We are
Explanation of Solution
Given:
Out of
The confidence interval is constructed for the population mean
Hence, the sample mean is fixed an no need to construct a confidence interval for this statistics.
Conclusion:
Therefore, we can conclude that by the confidence interval the mean of the sample is not defined.
b.
To explain: Whether the statement “We are
Answer to Problem 64E
The statement “We are
Explanation of Solution
Out of
By the notation
The population that is discussed in this case is all
Conclusion:
Hence, the mean number of people in the
Conclusion:
Here, in the statement it is said that the
c.
To explain: Whether the statement “The probability is
Answer to Problem 64E
The statement “The probability is
Explanation of Solution
Out of
The confidence level of an interval denotes the chance/ probability of the relevant parameter to be within the interval.
Here, the interval
Generally, a probability is expressed as a decimal or fraction. Hence, we should convert this percentage into a decimal to check the statement.
Conclusion:
Therefore we can conclude that the probability for the mean number of people in total number of households is between the confidence interval is
d.
To explain: Whether the statement “
Answer to Problem 64E
The statement “
Explanation of Solution
Out of
As mentioned in the above parts, the confidence interval is defined for the population mean. Hence all the estimations can be made only for the mean number of people in the total number of households in the city.
In the statement the number of peoples in each household is considered individually. It says there is a
Conclusion:
Therefore, we can conclude that the given confidence interval does not represent a proportion of the population.
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Chapter 8 Solutions
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