Question

A random sample of 100 observations from a normally distributed population possesses a mean equal to 78.4 and a standard devi

a. Find a 95​% confidence interval for μ.

b. What do you mean when you say that a confidence coefficient is .90​?

c. Find a 99​% confidence interval for μ.

d. What happens to the width of a confidence interval as the value of the confidence coefficient is increased while the sample size is held​ fixed?

e. Would your confidence intervals of parts a and c be valid if the distribution of the original population were not​ normal? Explain.

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solution Given na 100 X-784 S.D (6)=8.6 a) 95% confidence intuvai. R$2412 * 16. - 784–196* 806 1100 = 78.44 1.6656 - 46.7144,

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