Describe a research question of interest that will require a correlational analy
ID: 3225433 • Letter: D
Question
Describe a research question of interest that will require a correlational analysis. What additional research procedure you would have to do if you want to establish a causal relationship between the two variables if the correlation turned out to be significant. Be sure to cover the following:
A) List the two variables hypothesized to be correlated (.5 each)
B) Compose the null and alternative hypotheses in words (.5 each)
C) Additional research procedure to be done in order to establish a causal relationship between the two variables (1 point)
Explanation / Answer
A) List the two variables hypothesized to be correlated - We conduct a research to test whether the mean pressure applied to the driver’s head during a crash test is equal for each types of car. The variable 1 is mean head pressure and variable 2 is car type.
This requires a correlational analysis to know the correlation between mean head pressure and car type to check how significant these variables are correlated that is if value of one variable increases or decreases so does the value of the other variable. Correlation is a statistical measure that describes the size and direction of a relationship between two or more variables. A correlation between variables, however, does not automatically mean that the change in one variable is the cause of the change in the values of the other variable.
B) Compose the null and alternative hypotheses in words
H0: 1 = 2 = 3 - The mean head pressure is statistically equal across the three types of cars.
Ha: At least one mean pressure is not statistically equal.
C) Additional research procedure to be done in order to establish a causal relationship between the two variables
Causal relationship between two variables indicates that change in one variable is the result of the occurrence of the change in other variable; i.e. there is a causal relationship between the two variables.
We can use ANOVA as a additional research procedure to establish a causal relationship between the two variables. By Analysis of Variance (ANOVA), a hypothesis-testing technique we will test the equality of mean head pressure by examining the variances of samples taken for diffrerent car types. ANOVA allows one to determine whether the differences between the mean head pressure are simply due to random error (sampling errors) or whether the car type causes the mean head pressure in one group to differ from the mean head pressure in another.
ANOVA is based on comparing the variance (or variation) between the car types to variation within each particular car type. If the between variation of mean head pressure is much larger than the within variation of mean head pressure, the mean head pressure of different car types will not be equal. If the between and within variations of mean head pressure are approximately the same size, then there will be no significant difference between sample mean head pressure for different car types.