Question

In: Statistics and Probability

5. Suppose that researchers study a sample of 50 people and find that 10 are left-handed....

5. Suppose that researchers study a sample of 50 people and find that 10 are left-handed. (a) Find a 95% confidence interval for the population proportion that is left-handed.

(b) What would the confidence interval be if the researchers used the Wilson value p ̃ instead?

(c) Suppose that an investigator tests the null hypothesis that the population proportion is 18% against the alternative that it is less than that. If α = 0.05 then find the critical value pˆc. Using pˆ as the sample estimate, would the investigator reject the null?

(d) Suppose that researchers are using this critical value but, unbeknownst to them, the true, population proportion is 0.16. Find the power of the test.

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