超星 - 随堂测试5-1

单选题

When estimating a demand function for a good where quantity demanded is a linear function of the price, you should

A. not include an intercept because the price of the good is never zero.
B. use a one-sided alternative hypothesis to check the influence of price on quantity.
C. use a two-sided alternative hypothesis to check the influence of price on quantity.
D. reject the idea that price determines demand unless the coefficient is at least 1.96.

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单选题

The t-statistic is calculated by dividing

A. the OLS estimator by its standard error.
B. the slope by the standard deviation of the explanatory variable.
C. the estimator minus its hypothesized value by the standard error of the estimator.
D. the slope by 1.96.

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单选题

If the absolute value of your calculated t-statistic exceeds the critical value from the standard normal distribution, you can

A. reject the null hypothesis.
B. safely assume that your regression results are significant.
C. reject the assumption that the error terms are homoskedastic.
D. conclude that most of the actual values are very close to the regression line.

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单选题

Under the least squares assumptions (zero conditional mean for the error term, Xi and Yi being i.i.d., and Xi and ui having finite fourth moments), the OLS estimator for the slope and intercept

A. has an exact normal distribution for n > 15.
B. is BLUE.
C. has a normal distribution even in small samples.
D. is unbiased.

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单选题

The construction of the t-statistic for a one- and a two-sided hypothesis

A. depends on the critical value from the appropriate distribution.
B. is the same.
C. is different since the critical value must be 1.645 for the one-sided hypothesis, but 1.96 for the two-sided hypothesis (using a 5% probability for the Type I error).
D. uses ±1.96 for the two-sided test, but only +1.96 for the one-sided test.

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单选题

The p-value for a one-sided left-tail test is given by

A. Pr(Z - tact ) = φ(tact).
B. Pr(Z < tact ) = φ(tact).
C. Pr(Z < tact ) < 1.645.
D. cannot be calculated, since probabilities must always be positive.

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单选题

One of the following steps is not required as a step to test for the null hypothesis:

A. compute the standard error of <img>1.
B. test for the errors to be normally distributed.
C. compute the t-statistic.
D. compute the p-value.

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单选题

Finding a small value of the p-value (e.g. less than 5%)

A. indicates evidence in favor of the null hypothesis.
B. implies that the t-statistic is less than 1.96.
C. indicates evidence in against the null hypothesis.
D. will only happen roughly one in twenty samples.

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单选题

The only difference between a one- and two-sided hypothesis test is

A. the null hypothesis.
B. dependent on the sample size n.
C. the sign of the slope coefficient.
D. how you interpret the t-statistic.

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单选题

Using 143 observations, assume that you had estimated a simple regression function and that your estimate for the slope was 0.04, with a standard error of 0.01. You want to test whether or not the estimate is statistically significant. Which of the following possible decisions is the only correct one:

A. you decide that the coefficient is small and hence most likely is zero in the population
B. the slope is statistically significant since it is four standard errors away from zero
C. the response of Y given a change in X must be economically important since it is statistically significant
D. since the slope is very small, so must be the regression R2.

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