The regression function indicates the

A. average value the dependent variable assumes for a given value of the independent variable.

B. actual value the independent variable assumes for a given value of the dependent variable

C. average value the dependent variable assumes for a given value of the dependent variable

D. actual value the dependent variable assumes for a given value of the independent variable

In Simple Linear Regression the slope (b1) represents

A. predicted value of Y when X = 0.

B. the estimated average change in Y per unit change in X.

C. the predicted value of Y.

D. variation around the line of regression.

The width of a confidence interval estimate for a proportion will be

A. narrower for 99% confidence than for 95% confidence.

B. wider for a sample size of 100 than for a sample size of 50.

C. narrower for 90% confidence than for 95% confidence.

D. narrower when the sample proportion is 0.50 than when the sample proportion is 0.20.

If the p value is less than the level of significance in a two-tailed test,

A. the null hypothesis should not be rejected.

B. the null hypothesis should be rejected.

C. a one-tailed test should be used.

D. no conclusion should be reached.

In testing for differences between the means of 2 independent populations the null hypothesis is:

A. H0: Difference is positive

B. H0: No mean difference

C. H0: Mean difference is negative

D. H0: Mean difference is not equal to the test value.

If a particular batch of data is approximately normally distributed, we would find that approximately

A. 2 of every 3 observations would fall between +/-1 standard deviation around the mean.

B. 4 of every 5 observations would fall between +/-1.28 standard deviations around the mean.

C. 19 of every 20 observations would fall between +/-2 standard deviations around the mean.

D. All the above.

The process of using sample data to make guesses about an entire population is called:

A. Descriptive statistics

B. Statistical inference

C. data analysis

D. random sampling

Why do we create a scatter plot of the data in regression analysis?

A. To compute the error terms.

B. Because Excel calculates the function from the scatter plot.

C. To check for a relationship between X and Y.

D. To estimate predicted values.

In a right-skewed distribution

A. the median equals the mean.

B. the median is less than the mean.

C. the median is larger than the mean.

D. none of the above.

A 95% confidence interval estimate can be interpreted to mean that

A. if all possible samples are taken and confidence interval estimates are developed, 95% of them would include the true population mean somewhere within their interval.

B. we have 95% confidence that we have selected a sample whose interval does include the population mean.

C. Both of the above.

D. None of the above.

Sampling distributions describe the distribution of

A. parameters.

B. statistics.

C. both parameters and statistics.

D. neither parameters nor statistics.

In its standardized form, the normal distribution

A. has a mean of 0 and a standard deviation of 1.

B. has a mean of 1 and a variance of 0.

C. has an area equal to 0.5.

D. cannot be used to approximate discrete probability distributions.