18. Problem 15 in Chapter 10 described a study by Laughlin, Zander, Knievel, and Tan (2003) showing than groups of three people consistently outperformed the best of the individuals working alose on a letter --

De-numbers solstibition problem. The following data describe the number of trials seeded w solve each.

problems for a sample of n = 15 groups und a sample of - 15 aidividuals.

GOUDE Individuals

#=15.

1 15 M = 3.8 M = 4.7 55 = 15.4 S$= 182

a. Make a point estimate of how much better groups perform than individuals for the general population.

Estimate the mean difference in the number of trials needed for a solution )

h. Mike us inercal estimate of the mese difference Ro thie you are 955% confident that the true mean difference is an your interval.

c. Based on your uniwer to pan

b, what would be the decision from a hypothesis test evaluating Ibe significance of the mean difference using a two-billed test with u - 05. Explain your answer