Exam 16: Asking and Answering Questions About More Than Two Means

Before releasing a new product, a small company wants to compare the prices in the market for similar products from other brands presented in the same field. To do this, research has been conducted, and information has been collected for three similar brands. The information is presented in the table below. ​ Carry out an ANOVA test and find the F and P values.

When issuing a textbook, there is always a number of defective copies. The publishing house conducts a study to determine whether the number of defective copies depends on the format of the textbook. For the study, three random samples of textbook editions for the different book sizes were generated: a large portrait, a portrait, and a US letter, each of is the editions has approximately equal number of copies. The number of defective copies for each edition is indicated in the table below. ​ Carry out an ANOVA F test and interpret the results using the 95% confidence level.

A graduate student of the college conducted the following research. She considered four consulting companies and selected 13-15 approximately similar vacancies in each of these companies, which were posted on the official websites during the last year. The student was interested in the information about the wages indicated in the vacancies. Assume that you know that the student decided to conduct an F-test to compare the interested values, and draw the null hypothesis for this test in plain English. ​

A researcher wants to find out if the best sprinters of the planet improve the racing time at world championships in the 100 meters running discipline among men. He considers the results of the final racings of the last three world championships and compares the average time in each final racing. These data are represented in the table below ("https://www.iaaf.org/results/iaaf-world-championships-in-athletics"). ​ ​ Chose the correct null and alternative hypotheses statements.

A course work of a student is dedicated to the investigation of sleep. To begin with, it is important to establish whether there is a difference in the average duration of sleep for people of different age groups. For this purpose, the student considers several random samples to study four age groups. ​ Using a multiple comparison procedure identify differences between mean durations of sleep for considered age groups. Use 95% Tukey-Kramer confidence interval.