Last year, a consumer affairs investigator recorded the repair cost for 14 randomly selected iPhones. They found a sample mean of $187.52 and standard deviation of $29.49. They are also assuming that the population -- that is, the repair cost of all iPhones -- is approximately normal.Determine the 90% confidence interval for the mean repair cost for all iPhones.Show all relevant stepsExpress your final answer as an interval (value, value) and round to two decimal places as needed.If Apple (the manufacturer of iPhones) claimed that the mean repair cost of all iPhones last year was less than $170, would you believe their claim? Give a reason using the information given and your results into support your answer.

The random variable repair cost of all iPhones follows normal distribution. The sample size is 14.…

Answered: Last year, a consumer affairs…

Glencoe Algebra 1, Student Edition, 9780079039897, 0079039898, 2018

18th Edition

ISBN:9780079039897

Author:Carter

Publisher:Carter

Chapter10: Statistics

Section10.5: Comparing Sets Of Data

Problem 13PPS

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Last year, a consumer affairs investigator recorded the repair cost for 14 randomly selected iPhones. They found a sample mean of $187.52 and standard deviation of $29.49. They are also assuming that the population -- that is, the repair cost of all iPhones -- is approximately normal.

Determine the 90% confidence interval for the mean repair cost for all iPhones.

Show all relevant steps
Express your final answer as an interval (value, value) and round to two decimal places as needed.

If Apple (the manufacturer of iPhones) claimed that the mean repair cost of all iPhones last year was less than $170, would you believe their claim? Give a reason using the information given and your results into support your answer.

Definition Definition Measure of central tendency that is the average of a given data set. The mean value is evaluated as the quotient of the sum of all observations by the sample size. The mean, in contrast to a median, is affected by extreme values. Very large or very small values can distract the mean from the center of the data. Arithmetic mean: The most common type of mean is the arithmetic mean. It is evaluated using the formula: μ = 1 N ∑ i = 1 N x i Other types of means are the geometric mean, logarithmic mean, and harmonic mean. Geometric mean: The nth root of the product of n observations from a data set is defined as the geometric mean of the set: G = x 1 x 2 ... x n n Logarithmic mean: The difference of the natural logarithms of the two numbers, divided by the difference between the numbers is the logarithmic mean of the two numbers. The logarithmic mean is used particularly in heat transfer and mass transfer. ln x 2 − ln x 1 x 2 − x 1 Harmonic mean: The inverse of the arithmetic mean of the inverses of all the numbers in a data set is the harmonic mean of the data. 1 1 x 1 + 1 x 2 + ...

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