Exam 18: Nonparametric Methods

Two coffee-vending machines are studied to determine whether they distribute the same amounts.Samples are taken and the number of ounces is recorded for each machine. Calculate the value of T_A and T_B

A study was conducted to investigate the effect of an intervention protocol on IQ tests.Nine randomly selected students were tested. Calculate T^- and T⁺

Refer to the Mega - Stat/Excel output for the Wilcoxon signed rank test given in the table below. At a significance level of .01,which one of the following rejection point conditions is correct regarding the following null hypothesis? H₀: D₁ is shifted to the left of D₂

Five years ago,the average starting salary of a new college graduate with a major in marketing was $34,000.A random sample of 10 graduates from this year's graduating class of a local university yielded the following starting salaries in thousands of dollars: 28,36,25,37,35,24,38,45,39,and 36.The local university wants to determine if the median starting salary for marketing graduates has increased in the last five years. State the alternative hypothesis.Assume that the population of starting salaries in marketing is not normally distributed.

In a manufacturing facility producing fasteners,a foreman suspects that the diameter of the bolt produced by his first shift workers is greater than the diameter of the bolts produced by his second shift workers.He takes a sample of 5 bolts from the first shift and a sample of 4 bolts from the second shift and measures the diameters in inches.Below are the results from 5 first shift and 4 second shift observations.Distribution of bolt diameter measurements is not normally distributed. At = .05,can we conclude that his suspicion is correct?

In testing the significance of a population correlation coefficient using the Spearman's rank correlation coefficient,it is assumed that all possible combinations of values of variable X and variable Y have a bivariate normal probability distribution.

The EPA has stipulated that the PSI,"Pollution Standard Index" for clean air standards is to be no more than 100 on the average.A random sample of 9 days for the city of Acorn showed PSI readings of 144,85,90,120,150,105,93,130 and 115. The EPA wants to test to determine if Acorn's air is dirtier than the stipulated clean air standards.Assume the population of PSI readings is highly non-normal and state the null hypothesis.

Given the following sample data: .980,1.01,.970,.990,1.00,1.00,.980,.970,.980,and .999,run a sign test on H₀: M_d = 1.00 with a 2-sided alternative at $\alpha$ = .05.What do you conclude?

An assumption of the Wilcoxon rank sum test is that the variances of the two populations are equal.

Five years ago,the average starting salary of a new college graduate with a major in marketing was $34,000.A random sample of 10 graduates from this year's graduating class of a local university yielded the following starting salaries in thousands of dollars: 38,36,25,37,35,24,38,45,39,and 36.The local university wants to determine if the starting salaries have increased in the last five years.Assume that the population of starting salaries in marketing is not normally distributed.Which one of the following tests is appropriate for this problem?

A study was conducted to investigate the effect of an intervention protocol on IQ tests.Nine randomly selected students were tested. What is the rejection point T₀ for = .05?

A study was conducted to investigate the effect of an intervention protocol on IQ tests.Nine randomly selected students were tested. At = .05,test to determine if the protocol increases test scores.

Two NFL scouts are in the process of recruiting 7 college senior football players (receivers).After a careful review and evaluation,both scouts ranked the seven receivers in terms of their professional career prospects.If we want to determine whether the two scouts have similar opinions about the professional football career prospects of the seven players,state the null and alternative hypothesis.

If the population from which we sample is highly skewed to the right or to the left,then the population _________ might be a better measure of central tendency than the population mean.

The Spearman's rank correlation test can be used to study the relationship between two ordinal variables.

For eight randomly selected states,the following table lists the per capita beer consumption (in gallons)and the per capita wine consumption (in gallons) Test H₀: p_s = 0 vs H_A: p_s > 0 for the relationship between beer consumption and wine consumption at the state level at $\alpha$ = .05.

Parametric methods are ____________ more powerful than their nonparametric counterparts.