Deneme Sınavı Soruları

Homoscedasticity or equal variance of ui . All error terms have to have the same variance, technically, var(ui |Xi ) = σ2.

Zero average (mean) value of error term ui . Technically, the conditional mean value of ui is zero, E(ui |Xi ) = 0.

Autocorrelation or serial correlation between the disturbances.

The number of observations n must be greater than the number of parameters to be estimated.

Zero covariance between ui and Xi . There should not be a relation between these two terms.

To make policy decisions

to define a system, process, or function.

To predict inflation rate

To learn about income level

To predict of sales-based advertising

The model has one dependent variable

The model has one independent variable

The model has one dependent variable and one independent variable

The model has no variable

The model has one sample and one observation variable

Economics 

Hypothesis

Statistical inference 

Econometric inference 

Parameters

Population

Sample

Observation

Data

Cofficient

A restaurant might want to assess the
effectiveness of its recent advertising
campaign in boosting sales.

Macroeconomists may seek to evaluate the
efficacy of various government policies.

Developing new social relationships.

Almost every business might want to know
how their profits change as they expand.

Both government and private experts
should be interested in the price and
income elasticity of demand.

Data

Observation

Sample

Variable

Determinant

A cross-sectional

Time series

Nonexperimental

User 

Cost 

Making informed policy decisions

Understanding economic relationships

Forecasting economic conditions

Enhancing writing skills

Testing economic theories

Obtaining data

Regression analysis 

Hypothesis Testing

Forecasting

Prediction