ITM Final Exam

Lower tail

Alternative hypothesis, U<Variable, then it is a ___ test

Upper tail

Alternative hypothesis, U>Variable, then it is a ____test

Must be about a population and must deal with equality

Characteristics of a null hypothesis

X % of the total fluctuation around Y

Coefficient of determination interpretation

Type 2 error

Failure to reject a false null hypothesis, type of error considered a beta probability

Type 1

If a researcher rejects a true hypothesis, she has made a _______ error

if the null hypothesis is true, we reject it 1% of the time

If a test hypothesis has a Type 1 error probability of .01, we mean

a one-tail test should be utilized

If an economist wishes to determine where there is evidence that average family income community exceeds $25,000, what test should he utilize?

19

If we are testing for the difference between the means of 2 related populations with samples of n1=20 and n2=20 the number of degrees of freedom is equal to

no error

If, as a result of a hypothesis test, we reject the null hypothesis when it is false, then we have committed a...

the estimated average of Y increases by 2 units for each increase of 1 unit in X1, holding X2 constant

In a multiple linear regression problem involving 2 independent variables, if b1 is computed to be +2.0, it means that...

Has to fall between 0 and +1

In a multiple regression model, the value of the coefficient of multiple determination

It can be negative

In a multiple regression what is true of the value of the adjusted r2?

the variation around the line of regression is the same for each X value

In performing a regression analysis involving two numerical variables, x and y, we assume

Used to test the statistical significance of each B

In simple linear regression, the t-statistic or t-ratio is...

H0: ud=0

In testing for differences between the means of two related populations, the null hypothesis is...

a test for the difference between the means of 2 related populations

In what type of test is the variable of interest the difference between the observations rather than the observations themselves?

a two tail test for u is used

It is possible to directly compare the results of a confidence interval estimate to the results obtained by testing a null hypothesis if...

Linear trend, quadratic trend, exponential trend

Models that can be used to make predictions about long-term values of a time series are...

H0: B1=0

Null hypothesis for testing whether there is a linear relationship

Reject null

P-Value< alpha

Fail to reject the null

P-value > alpha

Type 1 error

Reject a true null hypothesis, considered a serious type of error, type of error considered alpha

False

T/F: Suppose, in testing a hypothesis about a population, the Z test statistic is computed to be 2.04. The null hypothesis should be rejected if the chosen level of significance is .01 and a two-tailed test is used

False

T/F: The larger the p-value, the more likely one is to reject the null hypothesis

False

T/F: for a given level of of significance, if the sample size is increased, the probability of committing a Type 1 error will increase

measures the proportion of variation in Y that is explained by X1 and X2

The coefficient of multiple determination r2

SSE

The least squares method in simple linear regression minimizes...

Trend

The overall upward or downward pattern of the data in an annual time series will be contained in the ________component

populations are approximately normal

The t test for the difference between the means of 2 independent populations assumes that the respective

populations are approximately normal

The t-test for the difference between the means of two independent populations assumes that the respective...

False

True or False: A regression had the following results: SST=82.55, SSE=29.85. It can be said that 73.4% of the variation in the dependent variable is explained by the independent variables in the regression

True

True or False: A trend is a persistent pattern in annual time-series data that has to be followed for several years

True

True or False: The coefficient of multiple determination r2 measures the proportion of variation in Y that is explained by X1 and X2

True

True or False: The interpretation of the slope is different in a multiple linear regression model compared to a simple linear regression model

False

True or false: When we test for differences between the means of 2 independent populations, we can only use a two-tailed test

True

True or false: when testing for differences between the means of 2 related populations, we can use either one-tailed or two-tailed test

n1+n2-2

Two sample independent equation for degrees of freedom

It gives greater weight to the earlier observation in the series

What abut the method of smoothing is not true

the model is a better predictor of Y than the sample mean, y bar

What do we mean when we say that a simple linear regression model is "statistically" useful?

Moving averages

What should not be used for short-term forecasts into the future?

The current smoothed value becomes the forecast

When using the exponentially weighted moving average for purposes of forecasting rather than smoothing...

Two tailed

alternative hypothesis is not equal to the variable, then it is a ______test

there is no unexplained variation

if the coefficient of determination (R2) is 1.00 then...

the proportion of total variation that is explained

the coefficient of determination (r2) tells us

the estimated average change in y per unit change in x

the slope (b1) represents

the variation around the sample regression line

the standard error of the estimate is a measure of

predicted value of Y when X=0

the y-intercept (b0) represents