Do teachers find their work rewarding and satisfying? An article reports the results of a survey...
Do teachers find their work rewarding and satisfying? An article reports the results of a survey of 391 elementary school teachers and 264 high school teachers. Of the elementary school teachers, 221 said they were very satisfied with their jobs, whereas 126 of the high school teachers were very satisfied with their work. Estimate the difference between the proportion of all elementary school teachers who are satisfied and all high school teachers who are satisfied by calalating a 95% d...
The article “Work-Related Attitudes” reports the results of a survey of 266 high school teachers and 395 elementary school teachers. Of the high school teachers, 126 said they are very satisfied with their jobs, whereas 224 of the elementary school teachers are very satisfied with their jobs. (a) Construct and interpret a 90% confidence interval for the true difference between the percentage of all high school teachers that are very satisfied and all elementary school teachers who are very satisfied....
1. Joseph Lister, a British physician, thought that infections might be controlled by use of carbolic acid as a disinfectant. To see if this helped patients, he noted that in 19 of 35 amputation cases where carbolic acid was not used, the patient lived. In contrast, 34 of 40 amputation cases where carbolic acid was used resulted in patients living. Using 95% confidence, estimate the change in survival rate for amputations by using carbolic acid as a disinfectant. 2. A...
We considered the differences between the reading and writing scores of a random sample of 200 students who took the High School and Beyond Survey in Exercise 5.21. The mean and standard deviation of the differences are x̄read-write = -0.545 and 8.887 points respectively. (a) Calculate a 95% confidence interval for the average difference between the reading and writing scores of all students. lower bound: points (please round to two decimal places) upper bound: points (please round to two decimal...
A researcher wants to determine whether high school students who attend an SAT preparation course score significantly different on the SAT than students who do not attend the preparation course. For those who do not attend the course, the population mean is 1050 (? = 1050). The 16 students who attend the preparation course average 1200on the SAT, with a sample standard deviation of 100. On the basis of these data, can the researcher conclude that the preparation course has...
The Insurance Institute for Highway Safety issued a press release titled "Teen Drivers Often Ignoring Bans on Using Cell Phones" (June 9, 2008). The following quote is from the press release. Just 1-2 months prior to the ban's Dec. 1, 2006 start, 11 percent of teen drivers were observed using cell phones as they left school in the afternoon. About 5 months after the ban took effect, 12% of teen drivers were observed using cell phones. Suppose that the two...
Question Help A research center reports on a survey taken in which they asked whether respondents have heard "good news" about the job market. The $30,000 or less per year with those making between $31,000 and $74,000. Well label the population of those making less than $30,000 as population 1 (low income), and those making between $31,000 and S74,000 as population 2 (middle income). A 95% confidence interval for the difference in proportions, 1 ow mns 2 is (-0.06,0.11). Interpret...
In an article in the Joumal of Advertising, Weinberger and Spotts compare the use of humor in television ads in the United States and in the United Kingdom. Suppose that independent random samples of television ads are taken in the two countries. A random sample of 400 television ads in the United Kingdom reveals that 141 use humor, while a random sample of 500 television ads in the United States reveals that 122 use humor (a) Set up the null...
10.2 A blind taste test is conducted to determine which of two colas, Brand A or Brand B, individuals prefer. Individuals are randomly asked to drink one of the two types of cola first, followed by the other cola, and then asked to disclose the drink they prefer. Results of the taste test indicate that 48 of 100 individuals prefer Brand A. Complete parts a through c. Do not reject the null hypothesis for the values of po between 0.39...
A random sample of 1028 adults in a certain large country was asked "Do you pretty much think televisions are a necessity or a luxury you could do without?" Of the 1028 adults surveyed, 527 indicated that televisions are a luxury they could do without. Complete parts (a) through (e) below. Click here to view the standard normal distribution table (page 1). Click here to view the standard normal distribution table (page 2). (a) Obtain a point estimate for the...