In a study of the relationship between birth order and college success, an investigator found that 126 in a sample of 180 college graduates were firstborn or only children. In a sample of 100 nongraduates of comparable age and socioeconomic background, the number of firstborn or only children was 54. Estimate the difference between the

Consider a random sample of 300 students in a university, 75 of them declared that they like playing football. Compute a point estimate of the proportion of all students who would like to play football.

Kris works for the MESA Air Pollution Study at UW, and studies the correlation be- tween air pollution and the disease atherosclerosis. Nationally, 40% of adults suffer from atherosclerosis. Kris suspects that the proportion of people with atherosclerosis in high- pollution areas is higher. In a random sample of 600 residents of high-pollution areas, he finds that 270 (45%) subjects have atherosclerosis. At the 1% level (α = .01), is this good evidence that people in high-pollution areas are more likely to have atherosclerosis? (a) Which of the following is the Ha ? (research claim or alternate) A. Ha : p ≥ 0.40 B. Ha : pb ≥ 0.40 C. Ha : p > 0.40 D. Ha : p > b 0.40 E. Ha : p > b 0.45 F. Ha : p > 0.45 G. Ha : pb ≥ 0.45 H. Ha : p ≥ 0.45 I. None of these Hint: First read the problem and using my notes (or Hawkes) for 9.1, set up H0 and Ha . Then pick the right Ha from the above list. Dont try to guess the answer from the above list. (b) Which of the…

Your statistics instructor often ponders the relationship between commute time and job satisfaction while driving back and forth to campus.  Your instructor hypothesizes that people with a shorter commute time will have higher degrees of job satisfaction.  Randomly sampling 600 Valley commuters, the instructor finds the following data listed in frequencies: Table 2: Commuters by Length of Commute and Job Satisfaction Job Satisfaction Number Who Commute 20 Minutes or Less Number Who Commute 21 to 40 Minutes Number Who Commute 41 Minutes or More Total Number for Each Level of Job Satisfaction Dissatisfied 10 60 140 210 Neutral 45 59 51 155 Satisfied 145 60 30 235 Total Number for Each Commute Time Range 200 179 221           1. Change frequencies to column percentages.