Question

Section 1: Scenarios

Read the following scenarios and state the appropriate test to analyze the data from the list of 7 tests below.

One-sample t-test Two-way ANOVA

Independent-samples t-test Repeated-measures ANOVA

Paired-samples t-test Correlation

One-way ANOVA

1. Squirrel weight: You are a behavioral ecologist interested in the eating habits of squirrels. You hypothesize that squirrels will eat more when the days are longer (e.g., eat more when there is 12 hours of daylight relative to 8 hours of daylight). You record the length of daylight (in hours) and record the weights of squirrels that you (humanely) caught and released throughout the year. Therefore, you have a series of daylight lengths and a corresponding series of squirrel weights. If you wanted to determine whether there is a relation between the length of daylight and squirrel weights, what test would you conduct?

1. Fire-retardant: You are a home builder and recently read about a new fire-retardant product that is supposed to ensure that wood will not burn for temperatures below 300 degrees Fahrenheit. Before selling this product to your customers, you decide to apply the new product to pieces of wood and measure the temperature at which the wood begins to burn to verify whether the new product does indeed prevent burning up to 300 degrees. If you wanted to determine whether temperatures for burning were different than 300 degrees, what test would you conduct?

1. Flood barriers: You are an engineer for the city of Brownsville, Texas and want to test a new flood barrier to determine whether it can hold up against the weather over time. You set up 10 of these new barriers and measure their durability when they were first posted, and then 4, 8, and 12 months after the barriers were posted. If you wanted to determine whether there was a change in durability of the new barrier over time, which test would you conduct?

1. Gas mileage: A new model of car is released and the manufacturer states that it can get 45 mpg. You are skeptical of this claim. Therefore, you ask a sample of individuals who purchased the car what the mpg for their car was for the past month. You want to determine whether mpg from your sample of individuals is different than what the manufacturer states (45 mpg). Which test would be most appropriate to answer this question?

1. Cholesterol: A study is conducted to examine the impact of a new medicine on the cholesterol level in adults. It is also hypothesized that the new medicine may work differently for women and men. Therefore, you recruit 20 women and 20 men and assign 10 women and 10 men to receive the medication. The remaining participants (10 women and 10 men) are assigned to receive a placebo. If you wanted to determine whether the new medication decreases cholesterol and whether there is a difference between women and men in response to the new medication, which test would you conduct?

1. Comparing weight loss programs: You conducted a study comparing the Get Fit and Get Buff weight loss programs between two samples of individuals where one sample participated in the Get Fit program and the other sample participated in the Get Buff program. You record weights from participants in each group at the end of the program. If you wanted to determine which group of individuals had lower body weights, which test would you conduct?

1. Smoking cessation: You are an experimental psychologist who is interested in characterizing the relative effectiveness of two treatments for smoking cessation: a pharmacological (medication) treatment and a contingency management (therapeutic) treatment. You recruit 60 cigarette smokers and randomly assign them to a Control Condition (placebo treatment), a Pharmacological Condition, and a Contingency Management Condition. After 30 days on each treatment, you ask participants how many cigarettes they have smoked in the past week to determine the effectiveness of each treatment. If you wanted to determine the effectiveness of the treatments, relative to each other and to the placebo, which test would you conduct?

1. Club soda: You are an experimental dentist who has heard that drinking club soda is damaging to teeth; however, you have been unable to find the source of this potential rumor. Therefore, to clear up whether club soda is actually damaging to teeth, you decide to survey patients at various dentist offices and ask for the number of club sodas they drink in a week and the number of cavities they have. If you wanted to determine whether there is a relation between drinking club soda and cavities, which test would you run?

1. Probiotics: Recent research suggests that probiotics (i.e., “gut bacteria”) can help in the production of serotonin in the stomach which may be important for targeting a potential treatment for balancing serotonin levels. However, no one is sure whether this translates to blood plasma levels of serotonin in the brain. To determine whether probiotics increase serotonin in blood plasma, you conduct an experiment where you give one group of participants a probiotic supplement and another group of participants a placebo. After one week, you collect blood plasma and measure the volume of serotonin in the participants blood. If you wanted to determine whether the probiotic supplement increased serotonin in the group of participants who received that treatment, relative to the group of participants who received the placebo treatment, which test would you conduct?

1. Cultural Competence: You are a community psychologist interested in the effectiveness of a cultural competence training on individuals’ recognition of their own implicit biases when they confront different cultures. Specifically, you recruit a sample of participants who enroll in the training program. For each participant, you collect baseline scores on a cultural competence scale and, after the training, reassess their cultural competence. If you wanted to determine whether the program is effective in increasing cultural competence according to the cultural competence scale, which test would you conduct?

Answer 1

Squirrel weight: Here we have two continuous variables which are the length of daylight and squirrel weights and we want to find whether there is any relation between these two continuous variables. Hence, in this case we will use the correlation test.

Fire-retardent: In this case, we want to know whether tempeartures for burning were different than 300 degrees. We have a sample of data which has only one continuous variable (temperature for burning). In this case, we will apply the one-sample t-test and check the null hypothesis that Mean temperatures for burning = 300 degrees.

Flood barriers: Here we want to know the change in durability of the new barrier over time. We have four samples of repeated values (10 times) of the durability of the new barriers. Hence, we want to compare the means of the variable at different times or between different samples. We will use a repeated-measures ANOVA here.

Gas mileage: Here, we have only one variable which is the gas mileage and we want to check whether the mean value differs from 45 mpg. There is only one sample and one variable. Hence, we will use a one-sample t-test.

Cholesterol: In this case, we have two factors (Placebo and control group) and Gender (Men and women) and we need to check the difference in mean values of cholesterol levels between these two-factors. Hence, we will use a two-way ANOVA here.

Comparing weight loss programs: We have two samples of individuals here which are independent we need to check the difference in the body weights between the two. Hence, we will use a independent samples t-test here.

Smoking cessation: In this case, we have different groups or conditions and we want to see the difference between the effectiveness of the treatments. We have one factor here. The participants are different in each treatment, hence it is not a repeated measures ANOVA. Therefore, it is a one-way ANOVA

Club Soda: We have two variables here which are continuous in nature which are number of club sodas they drink in a weak and no. of cavities. Hence, we will use the correlation test here.

Probiotics: We have two different samples here which is the control group and one is the placebo group. We need to check the difference in blood plasma levels. Hence, we will be using the independent samples t-test here.

Cultural competence: We have one sample of individuals here for which two data points are collected, one the baseline scores before the training and one after the training. The two data points are related to the participant & we need to check whether there is an increase in the cultural competence through the training. The data is paired in this case. Hence, we will use the paired samples t-test.