A+ Answers

1.         A negative 0.947 correlation coefficient has been found between two variables after examining 43 pairs of observations. What can be concluded?

                        a.         There is a strong positive relationship between the two variables.

                        b.         There is a strong negative relationship between the two variables.

                        c.         There is a weak positive relationship between the two variables.

                        d.         There is a weak negative relationship between the two variables.

2. A linear regression between Y and X produced the following equation for the least squares line:

                                                                                    = –4.13 + 2.1x                                                        

                        Which of the following statements concerning this relationship is true?

                        a.         For every one-unit increase in X, Y increases 4.13 units.

                        b.         For every one-unit increase in X, Y decreases 2.1 units.

                        c.         For every one-unit increase in X, Y decreases 4.13 units.

                        d.         For every one-unit increase in X, Y increases 2.1 units.

employment in years.

 Number of Workdays Absent            2          3          3          5          7          7          8

            Length of Employment (in yrs)         5          6          9          4          2          2          0

 Compute the Coefficient of Correlation, the R-Square, and the linear regression coefficients

4. The price-to-book value is a commonly used measure of whether a stock is over- or underpriced. The average price-to-book value for all gas utility stocks averaged 1.80 in 2010 and the standard deviation was 0.45. A random selection of 36 gas utility stocks in August, 2011 yielded a mean of 1.95.

 Set up the null and alternative hypotheses to test if the average price-to-book value of the August, 1999 selection is greater than the 1998 national average for gas utility stocks.

Determine the critical value using a = 0.05

c. Calculate the value of the test statistic

                                           d. What is your conclusion?

5. The e-mail usage for two different plants of a large company was compared at level of significance 0.05. Samples of 40 employees were selected at each plant. The mean number of e-mail messages sent per employee for one plant was 15.5 per week and the standard deviation was 5.0. For the other plant, the mean was 18.4 and the standard deviation was 1.6. For the test of equal population means versus unequal population means

state the null and alternate hypothesis

Calculate the test statistics

Decide whether the population means are different.

6 The following table shows the average number of daily e-mail messages that ACME Company  received over a six-week measurement period.     

Using Chi-Square test of hypothesis methdolology:

            a)         State the null and alternate hypothesis

b)                    Calculate the value of the test statistics

            c)         At 5% significance level what is your decision?

7- The following is a partial ANOVA table:

In 1999, a sample of 200 in-store shoppers showed that 42 paid by debit card. In 2004, a sample of the same size showed that 62 paid by debit card. A0 formulate appropriate hypotheses to test whether the percentage of debit card shoppers increased B) carry out the test at alpha = .01. c) find the p value, d) test whether normality may be ussumed. determine if this is a right tail, a left tail, or a two tail test. Showthe work and make a bell graph