independent group

(noun)

A statistical group of random variables that has the same probability distribution as the others, and that are all mutually independent.

Related Terms

Examples of independent group in the following topics:

  • Introduction

    • Typically, one group is given aspirin and the other group is given a placebo.
    • The groups are classified either as independent or matched pairs.
    • Independent groups mean that the two samples taken are independent, that is, sample values selected from one population are not related in any way to sample values selected from the other population.
    • The parameters tested using independent groups are either population means or population proportions.
    • When using the TI-83+/TI-84 calculators, we do not need to separate two population means, independent groups, population variances unknown into large and small sample sizes.

  • Using Two Samples

    • Typically, one group is given aspirin and the other group is given a placebo.
    • The groups are classified either as independent or matched pairs.
    • Independent groups mean that the two samples taken are independent, that is, sample values selected from one population are not related in any way to sample values selected from the other population.
    • The parameters tested using independent groups are either population means or population proportions.
    • Distinguish between independent and matched pairs in terms of hypothesis tests comparing two groups.

  • Group Conflict as a Barrier to Decision Making

    • Group dynamics, which involves the influence of social behavior, is the primary determining factor in the success of group outcomes.
    • Group cohesion, or positive feelings between individuals and productive working relationships, contributes to effective group decision making.
    • Loyalty to the group requires individuals to avoid raising controversial issues or alternative solutions, and there is a loss of individual creativity, uniqueness, and independent thinking.
    • The organization should set up several independent groups working on the same problem.
    • Each member should discuss the group's ideas with trusted people outside of the group.

  • Experimental Research

    • In this example, the independent variable is video game group.
    • Control groups are used to determine if the independent variable actually affects the dependent variable.
    • The control group demonstrates what happens when the independent variable is not applied.
    • The control group helps researchers balance the effects of being in an experiment with the effects of the independent variable.
    • Therefore, if there is a difference in the behavior of the two groups at the end of the experiment, the only reason would be the treatment given to the experimental group.

  • Graphical diagnostics for an ANOVA analysis

    • There are three conditions we must check for an ANOVA analysis: all observations must be independent, the data in each group must be nearly normal, and the variance within each group must be approximately equal.
    • For processes and experiments, carefully consider whether the data may be independent (e.g. no pairing).
    • Sometimes in ANOVA there are so many groups or so few observations per group that checking normality for each group is not reasonable.
    • The last assumption is that the variance in the groups is about equal from one group to the next.
    • Independence is always important to an ANOVA analysis.

  • t-Test for Two Samples: Independent and Overlapping

    • The two sample t-test is used to compare the means of two independent samples.
    • Paired t-tests are a form of blocking, and have greater power than unpaired tests when the paired units are similar with respect to "noise factors" that are independent of membership in the two groups being compared.
    • The independent samples t-test is used when two separate sets of independent and identically distributed samples are obtained, one from each of the two populations being compared.
    • For example, suppose we are evaluating the effect of a medical treatment, and we enroll 100 subjects into our study, then randomize 50 subjects to the treatment group and 50 subjects to the control group.
    • In this case, we have two independent samples and would use the unpaired form of the t-test .

  • Advantages and Disadvantages of Group Decision Making

    • Group decision making can lead to improved outcomes, but only if a variety of conditions pertaining to group chemistry are satisfied.
    • Group decisions are subject to factors such as social influence, including peer pressure, and group dynamics.
    • The sharing of information among group members is another advantage of the group decision-making process.
    • Group decisions take into account a broader scope of information since each group member may contribute unique information and expertise.
    • Loyalty to the group requires individuals to avoid raising controversial issues or alternative solutions, and there is a loss of individual creativity, uniqueness, and independent thinking.

  • Comparing Two Sample Averages

    • Student's t-test is used in order to compare two independent sample means.
    • If the sample sizes in the two groups being compared are equal, Student's original t-test is highly robust to the presence of unequal variances.
    • The independent samples t-test is used when two separate sets of independent and identically distributed samples are obtained, one from each of the two populations being compared.
    • We enroll 100 subjects into our study, then randomize 50 subjects to the treatment group and 50 subjects to the control group.
    • In this case, we have two independent samples and would use the unpaired form of the t-test.

  • Labor Interest Groups

    • Labor interest groups are a type of economic interest group.
    • There are a wide variety of types of economic interest groups, including labor groups which advocate on behalf of individual workers and trade organizations.
    • The strength of labor interest groups continued in the 19th century.
    • Another example is the Freelancers Union which provides health care for members who are independent workers.
    • This union also works as an agenda building organization, bringing attention to the challenges of freelance workers including the high tax burden for independent workers.

  • Simulating the study

    • Now, suppose the bankers' decisions were independent of gender.
    • The randomization of files in this simulation is independent of the promotion decisions, which means any difference in the two fractions is entirely due to chance.
    • What is the difference in promotion rates between the two simulated groups in Table 1.45?
    • How does this compare to the observed 29.2% in the actual groups?
    • This difference due to chance is much smaller than the difference observed in the actual groups.