The Literary Digest was an American magazine that ran from 1890–1938. The magazine was famous for correctly predicting presidential winners since 1916 based on poll results. In 1936, however, it erroneously predicted that Alfred Landon would defeat Franklin Delano Roosevelt. This fiasco ultimately resulted in the magazine going out of business. The reason for The Literary Digest’s incorrect results has been studied throughout the years and is a famous example in statistics classes. One reason that researchers have found for the faulty results is that even though the magazine polled ten million people, the return rate of the surveys was around 23%. What type of bias is this? voluntary response bias non-response bias self-interest study loaded questions sampling bias perceived lack of anonymity response bias

Students often confuse the concepts of Random Sampling and Random Assignment (probably because they both contain the same word "random"), but these are different tools designed to solve different problems. This discussion is designed for students to help each other build a complete understanding, and clearly separate these as two distinct concepts. Discuss the similarities and differences between these, as well as the research problems they are used to solve.

You saw back in Chapter 2 that the mean, median, mode, and midrange are used to indicate where data is centered in a data set, or in other words what a typical value in the set is. A question that is often asked is, "If they're all supposed to do the same thing, why is there more than one?" Isn't one enough? In this exercise, you will be given two small sets of data. For each set, a. find the mean, median, mode and midrange b. in your opinion, decide which of the measures BEST represents all the values in the set (best indicates a typical value), and which one does this the WORST. c. post your responses and justify them by explaining why Don't forget to respond to at least one of your classmate's posts. With this exercise, "more is better." I'll elaborate after the deadline. • Set A: the salaries of 10 employees at a company (in thousands of dollars): 50, 50, 50, 50, 50, 50, 50, 50, 50, 500 • Set B: the grades of 9 students on an exam: 20, 25, 30, 35, 40, 45, 100, 100, 100

There are many over-the-counter pain relievers. By the end of the semester, you have a tremendous headache and are looking for the most effective pain relief – too much statistics homework!  You conduct a study comparing the two most popular pain relievers and a placebo to see which works best. You use only subjects with headaches and record the amount of time (in minutes) it takes for their headache to go away after they receive medication. What statistical analysis should you perform? State the hypotheses. State the df and critical value. State the test statistic and value. State your conclusion – using the APA format

A scientist studied the spread of AIDS and concluded that 24% of people contracted the disease. There is a problem with this conclusion. What should the correct conclusion state?

Provide an example of a study, including the variables, level of measurement, and hypotheses, for which a researcher could appropriately choose two different statistics to examine the relations between the same variables. Explain your answer.

When reading a problem, one must be aware of the sample size to determine if it is a Z-score or T-score problem. True or false

You are a public health researcher.  You want to see if the average age that a person starts smoking has changed over time.  Smokers are recruited to answer a survey that asked at what age they started smoking.  You divided participants into two groups, one is participants under the age of 30 and the second for participants over the age of 30.  The average age for the two groups were compared. Which statistical test would be best to determine if there is a significant different in starting age between the two groups.     one-sample t-test     related samples t-test     independent samples t-test     ANOVA

several years ago, the Gallup Organization conducted a random survey of 1018 adults aged 18 or older living in the United States and asked if you had $1000 to spend. Do you think investing it in the stock market would be a good idea? The Gallup study concluded that 54% of those surveyed said they thought investing in the stock. Market was a good idea. A statician would like to take a random sample of 200 of those 1018 adults and ask them the same question again to see if people change their minds over time. Based on the Gallup survey a statician specs that 54% of their sample will say that investing $1000  in the stock market would be a good idea give or take 2.1% find the chance as a percentage that institutions random sample 51% or more of them would say that investing $1000 in the stock market is a good idea write your answer as a percentage.

In the NFL, Coaches can throw "challenge" flags if they believe officials have made an incorrect call on the field. Then, based upon further analysis, the call is either overturned (because the referees were incorrect) or upheld (referees were correct). In the first eight weeks of last NFL season, there were 316 challenges made, with 154 of those calls overturned. The NFL team owners used this data to begin a lawsuit that claimed referees were wrong more than 50% of the time in challenged situations. They want to perform statistical analysis before filing that lawsuit. For the following question, select the answer which correctly responds. 0.50