10. According to the empirical rule, if the data form a "bell-shaped" normal distribution, ________ percent of the observation will be contained within 1 (one) standard deviation around the arithmetic mean. (Points: 4)
11. The probability that a new advertising campaign will increase sales is asssessed as being 0.80. The probabliity that the cost of devolping the new add campaign can be kept within the original budget allocation is 0.40. Assuming that the two events are independent, the probability that the cost is kept withing budget and the campain will increase sales is: (Points: 4)
12. The statictical distribution used for testing the difference between two population variances is the ___ distribution. (Points: 4)
13. a "robust" test procedure is one which (Points: 4)
requires a sofphisticaed level of measurement.
requires a semi-circular shaped population.
is sensetive to slight violations in its assumptions.
is insensetive to slight violations in its assumptions.
14. Why would you use the Tukey-Kramer procedure? (Points: 4)
to test for normality
to test for homogeneity of variance
to test for independence of errors
to test for the differences in pairwise means
15. For a given level of significance, if the sample size is increased, the power of the test will (Points: 4)
stay the same
16. The standard error of the sample proportion is the largest when the sample proportion reaches (Points: 4)
17. An economist is interested in studying the incomes of consumers in a particular region. The population standard deviation is know to be $1,000. A random sample of 50 individuals resulted in an average income of $15,000. What sample size would the economist need to use if he wants a 95% confidence interval no wider than plus or minus $100? (Points: 4)
18. A 99% confidence intereval estimate can be interpreted to mean that (Points: 4)
if all possible samples are taken and confidence interval estimates are developed, 99% of them would include the true population mean somewhere within their interval.
we have 99% confidence that we have selected a sample whose interval does include the population mean.
both of the above
none of the above
19. The Y intercept (bo) represnts the (Points: 4)
the predicted value of Y when X = 0.
the change in estimated average y per unit change in X.
predicted value of Y.
variation around the sample regression line.
20. The slope (b1) represents (Points: 4)
the predictied value of Y when X = 0
the estimated average change in Y per unit change in X.
the predicted value of Y.
variation around the line of regression.
21. The least squares method minimizes which of the following? (Points: 4)
all the above
22. In performing a regression analysis involving two numerical variables, we are ssuming: (Points: 4)
the variances of X and Y are equal.
the variation around the line of regression is the same for each X value.
that X and Y are independent.
all of the above.
23. The strength of the linear relationship between to numerical variables may be measured by the (Points: 4)
coefficient of correlation
24. In a multiple regression mode, the value of the coefficient of multiple determination (Points: 4)
has to fall between -1 and +1.
has to fall between 0 and +1.
has to fall between -1 and 0.
can fall between any pair of real numbers.
The solution provides answers to multiple choice questions on statistics. Relevant workings are also included.