2 22 Write the null and alternative hypotheses
- Slides: 8
-2. 22 Write the null and alternative hypotheses. In the 1950’s only about 40% of high school graduates went on to college. Has that percentage changed?
Ho: p =. 4 Ha: p ≠. 4 The National Center for Education Statistics monitors many aspects of elementary and secondary education. In 1996, 31% of students reported that their mothers had graduated from college. In 2000, responses from 8368 randomly chosen students found that this figure had grown to 32%. Is this evidence of a change in education level among mothers? Perform the test and find the P value.
0. 047 In June 2010, a random poll of 800 working men found that 9% had taken on a second job to help pay the bills. Estimate the true percentage of men taking on a second job by constructing a 95% confidence interval.
(. 070 , . 110) I am testing to see if the sample proportion has changed. My test statistic is 2. 8. What is my P value?
. 0051 A magazine wants to poll car owners to see if they are happy with their vehicles. They will randomly select 450 owners of American made vehicles and 450 owners of Japanese vehicles. 76% of the owners of American cars and 78% of the owners of Japanese cars said they were happy with their vehicle. What is the standard deviation for the difference in proportions?
. 028 Women being treated for anorexia were randomly split into two groups, one group received Prozac, the other a placebo. Of the 49 who received Prozac, 35 were deemed healthy a year later, compared to 32 of the 44 who got the placebo. Find a 95% confidence interval for the difference of proportions.
(-0. 20 , 0. 17) Carpal tunnel can be treated with surgery or less invasive wrist splints. In September 2002, Time magazine reported on a study of 176 patients. Among the half that had surgery, 80% showed improvement after three months, but only 54% of those who used wrist splints improved. What is the standard error in the difference of the two proportions?
0. 068 Researches identified 450 people with cardiac disease, evaluated them for depression, and followed the group for 4 years. Of the 361 patients with no depression, 67 died. Of the 89 patients with depression, 26 died. Among people who suffer cardiac diseased, are depressed patients more likely to die than non depressed? Find the z score you would use to calculate P value.
