Practice Confidence Intervals (4.5) - Statistical Inference and Hypothesis Testing

Practice: Confidence Intervals

Lesson 4.5Statistical Inference and Hypothesis Testing

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9 questions

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4 cards from this section. Quick, good the night before a test.
Exercise
6 questions · about 4 min · pass mark 70%. Hints available.
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Quiz
3 questions · about 2 min · pass mark 70%. Hints available.
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6 sample questions

Question 1.
What is a confidence interval?
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Think about what it means to estimate a parameter.
Question 2.
What is the purpose of the population standard deviation in the confidence interval formula?
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Consider how variability impacts your estimates.
3Question 3.
What does a 95% confidence interval imply?
- It contains the true population parameter in 95% of cases
- It guarantees the true parameter is within the range
- It implies absolute certainty in estimates
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Think about how confidence intervals reflect sampling behavior.
4Question 4.
True or False: A wider confidence interval indicates greater precision in estimating the population parameter.
- True
- False
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Consider the relationship between width and certainty.
Question 5.
A researcher claims the average height of a species of tree is 15 feet. They collect a sample of 50 trees, which has a mean height of 14.5 feet and a standard deviation of 2 feet. Calculate the 95% confidence interval and discuss its implications.
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Use the provided formula and keep the critical z-value in mind for your calculations.
Question 6.
If a sample of 30 students has a mean score of 85 on a final exam with a standard deviation of 5, construct a 99% confidence interval. What does this say about the strength of your estimate?
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Remember to find the appropriate z-value for the 99% confidence level.

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