Describe two variables from chocoalte sales field work exper

Describe two variables (from chocoalte sales field work experience) that you believe might be related. Which method (correlation, simple linear regression, Chi Square test of independence) would be appropriate to use in order to determine if the relationship between these variables is significant? Justify your selection. Describe how the data would be collected on these two variables? What may be some difficulties in obtaining the data necessary to perform statistical inference?

Solution

sol) Using correlation we can find the relationship between two variables (chocolate sales field and work experience). It gives the values that how much correlation between two variables.

Different method for finding correlation

a) scatter plot

b) Karl pearson\'s correlation coefficient

Types of association

An association may be found between two variables for several reasons (show causal modeling figures):

• There may be direct causation, e.g. smoking causes lung cancer.

• There may be a common cause, e.g. ice cream sales and number of drownings both increase with temperature. • There may be a confounding factor, e.g. highway fatalities decreased when the speed limits were reduced to 55 mph at the same time that the oil crisis caused supplies to be reduced and people drove fewer miles

. • There may be a coincidence, e.g., the population of Canada has increased at the same time as the moon has gotten closer by a few miles.

Difficulties

• Random Sampling Required Sample correlation coefficients are only valid under simple random samples. If the data were collected in a haphazard fashion or if certain data points were oversampled, then the correlation coefficient may be severely biased. • There are examples of high correlation but no practical use and low correlation but great practical use. These will be presented in class. This illustrates why I almost never talk about correlation. • correlation measures ‘strength’ of a linear relationship; a curvilinear relationship may have a correlation of 0, but there will still be a good correlation.