The Graded Naming Test and sociocultural differences: Researchers often use z tests to compare their
The Graded Naming Test and sociocultural differences: Researchers often use z tests to compare their samples to known population norms. The Graded Naming Test (GNT) asks respondents to name objects in a set of 30 black-and-white drawings. The test, o
Suppose you were asked to analyze each of the situations described below. (NOTE: DO NOT DO THESE ...
[html]Suppose you were asked to analyze each of the situations described below. (NOTE: DO NOT DO THESE PROBLEMS!) For each, indicate which inference procedure you would use (from the list), the test st
Car colors According to Ward's Communication, 19% of sports car enthusiasts prefer a red color, ...
[html]Car colors According to Ward's Communication, 19% of sports car enthusiasts prefer a red color, 16.2% silver, 14.7% black, 14.1% green, 14% white, and 22% other colors. A sample of 250 cars at a NASCAR ra
Student progress The Comprehensive Test of Basic Skills (CTBS) is used by school district to assess ...
[html]Student progress The Comprehensive Test of Basic Skills (CTBS) is used by school district to assess student progress. Two of the areas tested are math and reading. A random sample of student results was r
Hospital stays Hospital nurses sampled records of 58 surgery patients. They wondered if length of ...
[html]Hospital stays Hospital nurses sampled records of 58 surgery patients. They wondered if length of surgery (in hours) might be related to the length of the hospital stay (in days). To find out, they create
Poverty In a study of how the burden of poverty varies among U.S. regions, a random sample of 1000 ...
[html]Poverty In a study of how the burden of poverty varies among U.S. regions, a random sample of 1000 individuals from each region of the United States recently yielded the information on poverty (based on d
Suppose you were asked to analyze each of the situations described below. (NOTE: DO NOT DO THESE ...
[html]Suppose you were asked to analyze each of the situations described below. (NOTE: DO NOT DO THESE PROBLEMS!) For each, indicate which inference procedure you would use (from the list), the test st
A college admissions counselor was interested in finding out how well high school grade point ...
[html]A college admissions counselor was interested in finding out how well high school grade point averages (HS GPA) predict first-year college GPAs (FY GPA). A random sample of data from first-year students was revi
A college admissions counselor was interested in finding out how well high school grade point ...
[html]A college admissions counselor was interested in finding out how well high school grade point averages (HS GPA) predict first-year college GPAs (FY GPA). A random sample of data from first-year students was revi
Could eye color be a warning signal for hearing loss in patients suffering from meningitis? British ...
[html]Could eye color be a warning signal for hearing loss in patients suffering from meningitis? British researcher Helen Cullington recorded the eye color of 130 deaf patients, and noted whether the patient's deafness had developed following treatm
Improving Efficiency A distribution company considers hiring a national training consultant in hopes ...
[html]Improving Efficiency A distribution company considers hiring a national training consultant in hopes of improving efficiency in deliveries. The national consultant agrees to work with 30 drivers for one w
Test identification Suppose you were asked to analyze each of the situations described below. (NOTE: ...
[html]Test identification Suppose you were asked to analyze each of the situations described below. (NOTE: Do not do these problems!) For each, indicate which procedure
Company executives wish to estimate the dollar amount that customers spend in one shopping visit to ...
[html]Company executives wish to estimate the dollar amount that customers spend in one shopping visit to their store. Initial tests were based on a small sample but now the executives double the sample size for a follow-up test. The main purpose of
A compensation specialist at a technology company wants to assess the competitiveness of the ...
[html]A compensation specialist at a technology company wants to assess the competitiveness of the salaries at his firm. He needs to know the mean salary of the firm's employees. He checks all the employee salaries using company records, and he used
An old myth claims that boys are better at math than girls. A high school guidance counselor ...
[html]An old myth claims that boys are better at math than girls. A high school guidance counselor collects the math grades from a random sample of 50 boys and another random sample of 50 girls. The guidance counselor then tested the hypothesis
The manager of a self-serve frozen yogurt shop, Purple Pear, knows that customers swirl different ...
[html]The manager of a self-serve frozen yogurt shop, Purple Pear, knows that customers swirl different amounts of the creamy concoction into their cups. She samples cups from 10 costumers she believes to be representative of the customers and weighs
A random sample of 150 teachers in an inner-city school district found that 72% of them had ...
[html]A random sample of 150 teachers in an inner-city school district found that 72% of them had volunteered time to a local charitable cause within the past 12 months. What is the standard error of the sample proportion?
Feral cats tend to be lighter than domestic cats, mainly due to a lack of regular access to food. An ...
[html]Feral cats tend to be lighter than domestic cats, mainly due to a lack of regular access to food. An animal shelter in Boston weighed a random sample of newly admitted stray cats over several weeks. They found that a 95% confidence interval for
Which statement correctly compares t-distributions to the normal distribution?I. t distributions are ...
[html]Which statement correctly compares t-distributions to the normal distribution? I. t distributions are also unimodal, mound shaped and symmetric. II.
Auto repairs An insurance company hopes to save money on repairs to autos involved in accidents. Two ...
[html]Auto repairs An insurance company hopes to save money on repairs to autos involved in accidents. Two body shops in town seem to do most of the repairs, and the company wonders whether one of them is gener
Blood pressure Researchers developing new drugs must be concerned about possible side effects. They ...
[html]Blood pressure Researchers developing new drugs must be concerned about possible side effects. They must check a new medication for arthritis to be sure that it does not cause an unsafe increase in blood
Scrubbers A factory recently installed new pollution control equipment ("scrubbers") on its ...
[html]Scrubbers A factory recently installed new pollution control equipment ("scrubbers") on its smokestacks in hopes of reducing air pollution levels at a nearby national park. Randomly timed measurements of
One common method of evaluating the performance of a mutual fund is to compare its returns to those ...
[html]One common method of evaluating the performance of a mutual fund is to compare its returns to those of a recognized benchmark such as an index of the returns on all securities of the type that the fund accumula
We have calculated a confidence interval based on a sample of n = 180. Now we want to get a better ...
[html]We have calculated a confidence interval based on a sample of n = 180. Now we want to get a better estimate with a margin of error only one third as large. We need a new sample with
We have calculated a confidence interval based upon a sample of n = 200. Now we want to get a better ...
[html]We have calculated a confidence interval based upon a sample of n = 200. Now we want to get a better estimate with a margin of error only one fifth as large. We need a new sample with
Suppose that a manufacturer is testing one of its machines to make sure that the machine is ...
[html]Suppose that a manufacturer is testing one of its machines to make sure that the machine is producing more than 97% good parts (H0 : p = 0.97 and HA
Not wanting to risk poor sales for a new soda flavor, a company decides to run one more taste test ...
[html]Not wanting to risk poor sales for a new soda flavor, a company decides to run one more taste test on potential customers, this time requiring a higher approval rating than they had for earlier tests. This higher standard of proof will increas
A statistics professor wants to see if more than 80% of her students enjoyed taking her class. At ...
[html]A statistics professor wants to see if more than 80% of her students enjoyed taking her class. At the end of the term, she takes a random sample of students from her large class and asks, in an anonymous survey, if the students enjoyed taking h
The manager of an orchard expects about 70% of his apples to exceed the weight requirement for ...
[html]The manager of an orchard expects about 70% of his apples to exceed the weight requirement for "Grade A" designation. At least how many apples must he sample to be 90% confident of estimating the true proportion within ± 4%?
A certain population is bimodal. We want to estimate its mean, so we will collect a sample. Which ...
[html]A certain population is bimodal. We want to estimate its mean, so we will collect a sample. Which should be true if we use a large sample rather than a small one? I. The distribution of our sample data will be clearly bimodal. II.
We have calculated a confidence interval based on a sample of size n = 100. Now we want to get a ...
[html]We have calculated a confidence interval based on a sample of size n = 100. Now we want to get a better estimate with a margin of error that is only one-fourth as large. How large does our new sample nee
Pew Research found that, in 2013, 50% of American adults favored allowing same-sex couples to marry ...
[html]Pew Research found that, in 2013, 50% of American adults favored allowing same-sex couples to marry legally. This is up from 48% in 2012. The 2013 estimate was based on a random sample of 1,501 adults. Assume th
Researchers conduct a study to test a potential side effect of a new allergy medication. A random ...
[html]Researchers conduct a study to test a potential side effect of a new allergy medication. A random sample of 160 subjects with allergies was selected for the study. The new "improved" Brand I medication was rando
The International Olympic Committee states that the female participation in the 2004 Summer Olympic ...
[html]The International Olympic Committee states that the female participation in the 2004 Summer Olympic Games was 42%, even with new sports such as weight lifting, hammer throw, and modern pentathlon being added to
The International Olympic Committee states that the female participation in the 2004 Summer Olympic ...
[html]The International Olympic Committee states that the female participation in the 2004 Summer Olympic Games was 42%, even with new sports such as weight lifting, hammer throw, and modern pentathlon being added to
Pew Research reports that 63% of the U.S. adult cell phone owners use their phone to go online. A ...
[html]Pew Research reports that 63% of the U.S. adult cell phone owners use their phone to go online. A company wants to target 16- to 24-year olds for advertising and they wonder if that age group has a similar patte
A state's Department of Education reports that 12% of the high school students in that state attend ...
[html]A state's Department of Education reports that 12% of the high school students in that state attend private high schools. The State University wonders if the percentage is the same in their applicant pool. Admis
The countries of Europe report that 46% of the labor force is female. The United Nations wonders if ...
[html]The countries of Europe report that 46% of the labor force is female. The United Nations wonders if the percentage of females in the labor force is the same in the United States. Representatives from the United
