234 



LINEAR REGRESSION AND CORRELATION 



Ch. 7 



early-feathering females, what is the probability that a fertile egg selected at 

 random will hatch into an early-feathering chick, sex disregarded? 



24. Referring to problem 22, suppose parents 2 and 4 are mated. If 4 fertile 

 eggs are to be incubated and all can be assumed to produce a live chick, what 

 is the probability that at least one early-feathering chick of each sex will be 

 hatched so that you could hope to develop a line of early-feathering chickens? 



Ans. 55/128. 



25. Some educators believe that tests can be developed which measure a 

 persons general ability to think critically. No particular field of subject matter 

 is involved. The following data are test scores derived from such a testing 

 program. The students were asked — but not required— to indicate the level 

 of their father's annual income for the preceding year. All samples have n = 20 

 and are assumed to be from normal populations. 



(1) = not over $5000. (2) = $5001 to $10,000. (3) = none stated. 



Use any or all of these data for problems 25 to 32 below. 



Do the two samples for freshmen men and women whose fathers earned not 

 more than $5000 indicate that freshmen women think more critically than 

 freshmen men, if this test is assumed to be reliable? 



26. Referring to problem 25, how do freshmen men compare with junior and 

 senior men whose fathers are in the lower income group? Show how the G-test 

 helps answer this question. Ans. G = 0.13; P > .10; accept H (fi F = Mj an(J s)- 



