Question

For randomly selected adults, IQ scores are normally distributed with a standard deviation of 15. For a simple random sample of 25 randomly selected college students, their IQ scores have a standard deviation of 18. Use a 5% level of significance; test the claim that the IQ scores of college students are less consistent (higher standard deviation) compare to the IQ scores of the general population.

Answer 1

Null Hypothesis ho? o IS Alternate hypothesis ha: o > 15 (Right tailed) Test statistics: we will use x2 Test statistics 2 x? (ny) s² &2 s- sample standand deviation = 18 na sample sire 25 2 х (18) Test = (25 - 1) * (is) x² Test - 34.56 Pralie method: df= n-1- 24 Palue - Rake ( x X?>x? >x² rest ) PC X?> 34.56) af = 34.56 using x² Table cat Pualue - 0.0152 Decisim! 20.05 Mence Pralue ** we fail to Reject Null Hypothesis (Ho) Have we At x=0.05 do not ↑ sufficient evidence that college students are less consistent