Suppose You Wanted to Determine If You Should Reject the Null

question 50

Multiple Choice

Suppose you wanted to determine if you should reject the null hypothesis that running a playing fast tempo (as opposed to slow) music in your store has no effect on sales. On 65 randomly selected days with fast tempo music on the average store sales is $2,345 with a sample standard deviation of 45, while on 75 randomly selected days with slow tempo music on the average store sales is $2,555, with a sample standard deviation of 65. What would be the proper t-stat for this hypothesis test?

• A) \(\frac { 2345 - 2555 } { \sqrt { \frac { 45 ^ { 2 } } { 65 } + \frac { 65 ^ { 2 } } { 75 } } }\)
• B) \(\frac { 2345 } { \sqrt { \frac { 45 ^ { 2 } } { 65 } + \frac { 65 ^ { 2 } } { 75 } } }\)
• C) \(\frac { 2345 - 2555 } { \sqrt { \frac { 45 } { 65 } + \frac { 65 } { 75 } } }\)
• D) \(\frac { 2345 - 2555 } { \sqrt { 45 ^ { 2 } + 65 ^ { 2 } } }\)

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Definitions:

Correlation Coefficient

A numerical indicator that determines the magnitude of the correlation between the relative fluctuations of two variables.

Regression Analysis

An approach in statistics for modeling how a dependent variable is related to one or more independent variables.

Dependent Variable

The variable in an experiment that is expected to change as a result of manipulations to the independent variable.

Residual

The difference between observed and predicted values in a regression analysis.