Use the information below to answer questions 56 Researchers

Use the information below to answer questions #5-#6

Researchers at Purdue University conducted an experiment to three methods of teaching reading. Students were randomly assigned to one of the three teaching methods, and their reading comprehension was tested before and after they received the instruction. The variable “change” is the change in reading score after-before. The one-way ANOVA output is below.

anova.fit<-aov(change~instruction)

summary(anova.fit)

                            Df Sum Sq Mean Sq F value Pr(>F)

instruction 2 383.7 191.86   4.918 0.0104 *

Residuals   63 2457.7 39.01                

The p-value of 0.0104 indicates that

a) There is no population mean reading score change among the three instruction methods.

b) There is at least one population mean reading score difference among the three instruction methods.

c) There is a population mean reading score difference among only two of the three methods.

d) None of the above.

Suppose you wanted to maintain an overall Type I error rate of 0.10 and if you were going to conduct multiple comparison t-tests to further investigate the differences (if any) what would you significance level would you use?

a) 0.10

b) 0.10/2

c) 0.10*2

d) 0.10/3

e) 0.10*3

Solution

There is no population mean reading score change among the three instruction methods.   0.10/2