STATISTICAL TECHNIQUES AND TOOLS
CONFIDENCE INTERVALS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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A random sample of 9 refrigerators has a mean cost of $1263 and a standard deviation of $530.75. Construct a 90% confidence interval for the average cost of a refrigerator.
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(933.93, 1592.40)
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(934.26, 1921.47)
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(605.19, 1921.47)
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(650, 2300)
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Explanation:
Detailed explanation-1: -Calculating a C% confidence interval with the Normal approximation. ˆp±z√ˆp(1−ˆp)n, where the value of z is appropriate for the confidence level. For a 95% confidence interval, we use z=1.96, while for a 90% confidence interval, for example, we use z=1.64.
Detailed explanation-2: -The critical z-score values when using a 95 percent confidence level are-1.96 and +1.96 standard deviations. The uncorrected p-value associated with a 95 percent confidence level is 0.05.
There is 1 question to complete.