Psy 315 Week 3 Study

Week 3 Practice Problems

1. The class handout cites 3 basic purposes for studying statistics: data reduction, inference, and identification of relationships. In your own words, describe these three ideas in a couple of sentences each.

Why do we study statistics?

We study statistics for 3 reasons below:

Data Reduction: Transforming the digital information into simple form.

Inference: Making a meaningful conclusion based on the data is Inference in simple words. To minimize the duplicate data and make it to meaningful information.

Identification of Relationships: Relationship between two variables or sets of data. Example: relationship between student’s studies and their results.

2. Label each of the following as either data reduction, inference,

investigating the difference in results of using two different types of plant food

Ans: identification of Relationship because trying to identify difference between two types of food.

h. calculating the mean score on a final exam for a class of 100 students

Ans: data reduction because trying to reduce everything and shows meaningful part.

i. studying whether exposure to a certain type of chemical results in more frequent cancer diagnoses

Ans: Inference because it tries to conclude how certain types of chemical results in more frequent cancer diagnoses.

3. Tell which type of sampling is used (random, cluster, systematic, convenience, and stratified and give clear reasons to support your answer.

a. A researcher wants to find out how many students support the new bylaw guidelines for the Campus Student Government. She stands outside of Massie Hall and asks all students entering/exiting the building on Monday, Wednesday, and Friday.

Ans. Cluster sampling because its taking particular

A superintendent wants to do a study on poverty level versus student achievement levels in elementary students. His district has 18 elementary schools. He randomly chooses 6 of those schools, then includes all students from these 6 schools in his study.

Ans. Convenience Sampling

c. A researcher is planning to analyze the effect of multiple strategies to teach fractions to 6th – graders in Happy Valley School District. She assigns each 6th – grader a number and uses a random number generator to select students for each of her research groups.

Ans. Systematic Sampling because she assigns a random nth number to select students for each of her research groups.

d. A teacher wants to know whether a particular teaching strategy is more beneficial for boys or girls. She puts all girls’ names in one hat, and all boys’ names in the other hat. She then selected 10 boy and 10 girls to participate in her study.

Ans. Stratified Random Sampling because she chooses students equally from girls and boys group.

e. A researcher wants to analyze the issues that teacher’s in her district believe to be detrimental to student achievement. He prints a list of all 2,200 district employees and choose every 8th person on the list to be in his