Non Parametric Testing Flashcards
The investigator have no prior knowledge about the distribution of the sampled population and attempts to guess the distribution which result to serious error of the decision.
non parametric test
does not identify or specify the distribution of the population from which the sample were drawn
non parametric test
is a statistical procedure in which no hypothesis is made about a specific values of the population parameters
non parametric test
advantages of non parametric test
involve easy computation, fewer mathematical details, and easier to understand and to apply;
make it possible to work with small sample size, and very helpful to the experimenter involved in a pilot studies or dealing with rare types of characteristics
. In multi-sample cases, there are available nonparametric tests for testing hypothesis concerning observations drawn from several different populations without checking the assumptions about the population;
Probability statements associated with most nonparametric are exact probabilities, which are ____ of the shape of the population.
independent
- disadvantages of non parametric testing
may be used to test data that are measured only on a nominal or ordinal data;
that if in fact all parametric assumptions were satisfied in the data the values were of the required level of measurement, nonparametric tests would disregard much of the information contained in the data.
nonparametric tests when applied to data which are nearly normal or nearly normal are not so powerful as the equivalent parametric method.
major characteristics of the chi-square distribution are:
positively skewed
non-negative
there is a family of chi-square distribution
Chi square hypothesis
H1: There is a difference between the observed and expected frequencies.
Ho: There is no difference between the observed and expected frequencies
critical value in chi-square test
k-1 where k is the number of categories
- The U.S. Bureau of the Census indicated that 63.9% of the population is married, 7.7% widowed, 6.9% divorced (and not re-married), and 21.5% single (never been married). A sample of 500 adults from the Philadelphia area showed that 310 were married, 40 widowed, 30 divorced, and 120 single. At the .02 significance level can we conclude that the Philadelphia area is different from the U.S. as a whole?
what is the null hypothesis
The distribution regarding marital status in Philadelphia is the same as the rest of the United States
- The U.S. Bureau of the Census indicated that 63.9% of the population is married, 7.7% widowed, 6.9% divorced (and not re-married), and 21.5% single (never been married). A sample of 500 adults from the Philadelphia area showed that 310 were married, 40 widowed, 30 divorced, and 120 single. At the .02 significance level can we conclude that the Philadelphia area is different from the U.S. as a whole?
what is the alternative hypothesis
The distribution of marital status in the Philadelphia area is different from that in the U.S. population
- can be used to test for a relationship between two nominal scaled variables, where one variable is independent of the other.
chi-square test
is used to investigate whether two traits or characteristics are related.
contigency table
contigency table analysis according to two criteria:
usual hypothesis testing with
- degrees of freedom
- expected frequency
when to use chi-square?
When you want to know if there is an association between two categorical (nominal) variables (i.e., between an exposure and outcome)
Smoking (yes/no) and lung cancer (yes/no)
what test is used
chi-square test
Obesity (yes/no) and diabetes (yes/no)
what test is used
chi-square test
What does a chi-square test tell you?
If the observed frequencies of occurrence in each group are significantly different from expected frequencies (i.e., a difference of proportions)
Usually, the ___ the chi-square statistic, the greater likelihood the finding is significant,
higher
Chi square requires that there be ___ or more in each cell of a 2x2 table and 5 or more in 80% of cells in larger tables. No cells can have a zero count.
5
Chi-squared formula is not applicable in ___
smal samples
If fewer than 5 observations are used per cell, what is used instead of Chi-square test?
Fisher’s exact test
Applicable in the case of two dependent or related samples which aimed to detect significant differences between the two groups.
wilcoxon signed test
Applicable in the case of two dependent or related samples which aimed to detect significant differences between the two groups.
wilcoxon signed test
Alternative of the t-test for the two dependent or correlated samples.
wilcoxon signed test
- A researcher wishes to determine if there is systematic difference between the readings of the two digital weighing scales
what is the null and alternative hypothesis
Null Hypothesis
There is no systematic difference between the readings of the two digital weighing scales.
Alternative Hypothesis
There is a systematic difference between the readings of the two digital weighing scales.
- The Gagliano Research Institute for Business is comparing the research and development (R&D) as a percent of income for a sample of glass manufacturing firms for 2000 and 2001. At the 0.05 significance level, has the R&D expense declined?
what is the null and alternative hypothesis
null: The R&D expense as a percent of income for glass manufacturing firms in 2001 is equal to or greater than that in 2000.
alternative: The R&D expense as a percent of income for glass manufacturing firms in 2001 has declined compared to 2000.
Used to determine if two independent samples came from the same or equal populations.
wilcoxon rank-sum test
No assumption about the shape of population is required.
Each sample must contain at least 8 observations.
The data must be at least ordinal scale.
what test
wilcoxon rank-sum test
for wilcoxon rank-sum test, at least ___ observations should be present
8
the data must be at least ___ in wilcoxon rank-sum test
ordinal
Hills Community College purchased two vehicles, a Ford and a Chevy, for the administration’s use when travelling. The repair costs for the two cars over the last three years is given. At 0.05 significance level, is there a difference in the two distributions?
what is the null and alternative hypothesis
null: There is no difference in the distributions of repair costs for the Ford and Chevy vehicles.
alternative: There is a difference in the distributions of repair costs for the Ford and Chevy vehicles.
- Used to compare three or more samples to determine if they came from equal populations
kruskal-wallis test analysis of variance by ranks
The ___ scale of measurement is required for Kruskal-Wallis Test Analysis of Variance
ordinal
It is an alternative to the one-way ANOVA
Kruskal-Wallis Test
for Kruskal Wallis, each sample should have how many observations
at least five
The chi-square distribution is the test statistic for this
Kruskal-Wallis Test Analysis of Variance By Ranks
Keely Ambrose, director of Human Resources for Miller Industries, wishes to study the percent increase in salary for middle managers at the four manufacturing plants. She gathers a sample of managers and determines the percent increase in salary from last year to this year. At the 5% significance level can Keely conclude that there is a difference in the percent increases for the various plants
what is the null and alternative hypothesis
null: There is no difference in the percent increases in salary for middle managers across the four manufacturing plants.
alternative: At least one plant has a different percent increase in salary for middle managers compared to the others.
- tests the hypothesis that k repeated measures or matched groups come from the populations with identical medians.
friedman two-way anova
Decision rule for Friedman Two-way ANOVA
Reject the Ho if the computed Fr is greater than tabulated chi-square value.
The following data represent the grades of 8 students in Math, Science, and Filipino. Test the hypothesis that there is no significant difference between the performance of students in the three subjects.
state the null and alternative hypothesis
null: There is no significant difference in the performance of students across the three subjects (Math, Science, and Filipino).
alternative: There is a significant difference in the performance of students in at least one of the three subjects.
- Reports the association between two sets of ranked observations
spearman’s coefficient of rank correlation
Similar to Pearson’s coefficient of correlation, but is based on ranked data.
spearman’s coefficient of rank correlation
Ho and Ha of Spearman’s coefficient of rank correlation
Ho: Rank correlation in population is 0
H1: Rank correlation in population is not 0.