9. A social psychologist plans to conduct an experiment with a random sample of 49 children from some school district Before conducting the experiment, the psychologist checks how this sample compares to national norms on several variables that could affect the re- sults of the experiment. The IQ scores for the 49 children have 103 and s = 14. The national population inean IQ equals 100. Is it plausible that the mean of the population of children in the school district from which these students were sampled equals 100

a) Conduct a lest of Ho: 100 against H: 100. Report the P-value, and inter- piel.

b) Make a decision about / using a = .05.

c) Construct a 95% confidence interval for u, and contrast the types of information ob- tained with the two inference methods. tests and confidence intervals.

d) Does it make sense to "accept He" in part (b)? Why or why not?

e) What conclusion applies for cach of the following a-levels: (i) = .20, (ii) = .10, (iii) = .01. Why is a 20 not typically used in practice?