1. Intro to Stats and Collecting Data

True or False: A simple random sample is always preferred because it obtains the same information as other sampling plans but requires a smaller sample size.

Determine whether you would take a census or use a sampling. If you would use a sampling, determine which sampling technique you would use. Explain.

The average distance traveled to a stadium by 55,000 spectators

Identify the sampling technique used, and discuss potential sources of bias (if any). Explain.

Questioning teachers as they leave a faculty lounge, a researcher asks 45 of them about their teaching styles.

A regional manager runs the day-to-day operations of three branches of a chain restaurant. Each location is roughly the same size and employs approximately the same number of workers. The manager is interested in streamlining policies across each location, so he decides to survey 10 random employees in each branch about certain processes. Is this a simple random sample? Is it a representative sample?

A researcher wants to study the effects of sleep deprivation on motor skills. Eighteen people volunteer for the experiment: Jake, Arya, Xavier, Nyla, Shaniece, Chen, Juan, Hana, Nia, Ansel, Liam, Bruno, Mei, Zoey, Kayla, Liam, Sofia, and Kai. Use a random number generator to choose nine subjects for the treatment group. The other nine subjects will go into the control group. List the subjects in each group. Tell which method you used to generate the random numbers.

Identify the sampling technique used, and discuss potential sources of bias (if any). Explain.

Soybeans are planted on a 48-acre field. The field is divided into one-acre subplots. A sample is taken from each subplot to estimate the harvest.

What is replication in an experiment? Why is replication important?

Determine whether the statement is true or false. If it is false, rewrite it as a true statement.

The method for selecting a stratified sample is to order a population in some way and then select members of the population at regular intervals.

200 students volunteer for an experiment to test the effects of sleep deprivation on memory recall. The students will be placed in one of five different treatment groups, including the control group.

Explain how you could design an experiment so that it uses a randomized block design.

"Researchers in Japan tested the effect of cannabidiol (CBD) in treating late teenagers with social anxiety disorder (SAD). Thirty-seven 18- to 19-year-old teenagers with SAD took part in the study. The patients were assigned at random to receive a daily dose of either CBD or a placebo for 4 weeks. Symptoms were measured using The Fear of Negative Evaluation Questionnaire and the Liebowitz Social Anxiety Scale at the beginning and end of the treatment. (Source: Frontiers in Psychology)

Identify a potential problem with the experimental design being used and suggest a way to improve it."

Describe a circumstance in which stratified sampling would be an appropriate sampling method.

Identify the sampling technique used, and discuss potential sources of bias (if any). Explain.

Questioning university students as they leave a college cafeteria, a researcher asks 342 students about their eating habits.

Systematic Sample To predict the outcome of a county election, a newspaper obtains a list of all 945,035 registered voters in the county and wants to conduct a systematic sample.

Determine k if the sample size is 130.

A 24-hour gym is interested in whether they should purchase a new rowing machine, so they decide to survey their active members to get their opinion. They use a random number generator to obtain a sample of gym ID numbers and ask all people selected about their opinion. They can collect the data easily, as all selected respondents happen to be enrolled in fitness classes in the early afternoons. Is this a simple random sample? Is this a representative sample?

A quality control manager wants to see how many defective products come off the line on average per day. They select three random cases of units at the end of the day to test how many defective units are in one of the three cases. What type of sampling method is this?