Previous research has shown that the mean number of ballpoint pens Americans use per year is 4.3 with a standard deviation of 1.17. You believe that amount is too high since computers are used so often this day and age. You randomly select 20 people and find the average to be 3.8 ballpoint pens per year. Assuming normality, is there evidence to show that the mean has decreased? What is the decision for this hypothesis test? Previous research has shown that the mean number of ballpoint pens Americans use per year is 4.3 with a standard deviation of 1.17. You believe that amount is too high since computers are used so often this day and age. You randomly select 20 people and find the average to be 3.8 ballpoint pens per year. Assuming normality, is there evidence to show that the mean has decreased? What is the decision for this hypothesis test? Reject the null because the test statistic is in the critical region and the p-value is less than alpha. Reject the null because the test statistic is in the critical region and the p-value is greater than alpha. Fail to reject the null because the test statistic is not in the critical region and the p-value is greater than alpha. Fail to reject the null because the test statistic is not in the critical region and the p-value is less than alpha.

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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Previous research has shown that the mean number of ballpoint pens Americans use per year is 4.3 with a standard deviation of 1.17. You believe that amount is too high since computers are used so often this day and age. You randomly select 20 people and find the average to be 3.8 ballpoint pens per year. Assuming normality, is there evidence to show that the mean has decreased? What is the decision for this hypothesis test?

Reject the null because the test statistic is in the critical region and the p-value is less than alpha.

Reject the null because the test statistic is in the critical region and the p-value is greater than alpha.

Fail to reject the null because the test statistic is not in the critical region and the p-value is greater than alpha.

Fail to reject the null because the test statistic is not in the critical region and the p-value is less than alpha.

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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