Answered: A researcher polled a sample of 1087…

MATLAB: An Introduction with Applications

6th Edition

ISBN:9781119256830

Author:Amos Gilat

Publisher:Amos Gilat

Chapter1: Starting With Matlab

Section: Chapter Questions

Problem 1P

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Question

A researcher polled a sample of

1087

adults in the year

2010

, asking them how many hours per week they spent on the Internet. The sample mean was

10.49

with a standard deviation of

14.21

. A second sample of

1046

adults was taken in the year

2012

. For this sample, the mean was

9.45

with a standard deviation of

13.89

. Assume these are simple random samples from populations of adults. Can you conclude that the mean number of hours per week spent on the Internet differs between

2010

and

2012

? Let

μ1

denote the mean number of hours spent on the Internet in

2010

. Use the

=α0.10

level and the

-value method with the TI-84 calculator.

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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