Performing a regression analysis variables


1. In performing a regression analysis with two numerical variables, we are assuming :

a.The variances of x and y are equal .

b.The variation of the regression line is the same for each value of y

c.The variables x and y are independent

d.The variation of the regression line is the same for each value of x

2. The value of Pearson correlation coefficient :

a. It lies between -1 and 0

b . It is between -1 and 1

c . is abut between 0 and +1

d . It is among any real numbers

3.The degree of association of the linear relationship between two numeric variables can be measured by :

a. Dispersion diagram

b . Correlation coefficient

c . Pending

d . intercept

4. Do not add a new variable to a multiple regression model if that variable causes :

a. r2 adjusted decrease

b. r2 decrease

c.La total sum square ( SCT ) decrease

5. In a regression model and if each point of the sample is above the regression line (all errors are 0), then:

a. the correlation coefficient is 1 or -1 .

b . the correlation coefficient is -1 .

c . the correlation coefficient is 0

6. Say which one (s ) is (are) the most appropriate expression to fill the ESPACI : _______ is the variation along the regression line (SC = sum of squares )

a. SCR

b. SCT

c. SCE

7. Control charts for attributes are :

a. graphic m .

b . graphic p .

c . r graphics .

d . graphics c .

8. A company is implementing a new quality control program . Items are listed and classified as defective or not defective. The type of control chart is one that should be used .

a. control chart for variables

b . graphic r

c . chart control limits

d . control chart for attributes

9. Control limits are obtained as :

a. process average + 1 standard deviation.

b.promedio process + 3 standard deviations

c . process average + 2 standard deviations

10. To select a model to tell the future:

a. do a residual analysis

b. measure the residual error

c. utilize parsimony principle

d. all of the above

11. If the seasonal index for July is 0.7, then sales in July tend to:

a. be lower than 30% in an average month

b. be lower than 70% in an average month

c. be 30% higher than in an average month

12. In an asymmetric distribution to the right:

a. the median is equal to the average.

b. the median is less than the average

c. the median is greater than the average

13. When we study the simultaneous responses of two categorical variables we build:

a. a contingency table

b. a frequency table

c. a table of cumulative frequencies

d. a histogram

14. Which of the following readings obtained is not of central tendency?

a. Half

b. Median

c. Fashion

d. Q3

15. In a perfectly symmetrical distribution:

a. the range is equal to interquartile range.

b. the interquartile range is equal to the average

c. the median is equal to the average

d. the variance is equal to the standard deviation

16. According to the empirical rule, if the data come from a normal distribution, ______ percent of the observations are between 2 standard deviations below the mean and between 2 standard deviations above average:

a. 68.26

b. 88.89

c. 93.75

d. 95.44

17. Ticket selection of a bag is an example of:

a. sampling with replacement

b. sampling without replacement

c. subjective probability

18. The simple probability is also called:

a. marginal probability

b. joint probability

c. conditional probability

d. Bayes Theorem

19. The standard normal distribution:

a. has mean 0 and standard deviation 1

b. has mean 1 and standard deviation 0

c. It has an area equal to 0.5

d. It can not be used to approximate discrete probability distributions

20. Sampling distributions describe the distribution of:

a. parameters

b. statistical

c. of both parameters and statistical

d. nor parameters nor statistical

21. When the sample size for a proportion is given a confidence level, and a sampling error is determined as close to 0.50 the p is estimated will be required sample size _____.

a. less

b. higher

c. the sample size is not affected

d. It can not be determined

22. The "t" distribution.

a. It assumes that the population is normally distributed

b. It approximates the normal distribution when the sample size grows

c. It has more tails areas in the normal distribution

d. all are correct

23. Which of the following will be an appropriate null hypothesis?

a. the mean of a Populations equal to 55

b. the mean of a sample is equal to 55

c. the mean of a population is greater than 55

d. Only (A) and (C) are true

24. For a given level of significance if the sample size grows:

a. test power grow

b. They will have more answers to collect and calculate

c. It will be skewed to the right of the mean

d. It has no effect on the direct results

25. A tabular presentation showing the output for each alternative decision under the different natural states is called:

a. matrix payback period (payback period matrix)

b. decision tree

c. decision matrix

d. payment decision matrix (a payoff table)

26. Blossom's flowers buying roses to sell for Valentine's Day. Roses are bought at $ 10. a dozen and sell for $ 20 a dozen. Any rose that is not sold that day can be sold for $ 5 a dozen. The owner buy from one to three items of roses for Valentine's Day, 100, 200, 400 dozen roses. The matrix payment to buy 200 dozen roses and sell 100 dozen at a high rate:

a. $ 2.000

b. $ 1.000

c. $ 500

d. $ -500

27. The overall pattern of motion or persistent, long-term up or down the data in a time series of annual ________ be a component.

a. trend

b. cyclic

c. irregular

d. seasonal

28. Regular fluctuations that occur in each period of 12 months would be a component _______.

a. trend

b. cyclic

c. irregular

d. seasonal

29. In 2008, the total payroll for the New York Yankees was $ 209.1 million, while the total payroll for the Tampa Bay Rays was about $ 43.8 million, or about one-fifth of the Yankees. Many people have suggested that some teams can compare winning seasons and championships spending a lot of money on the most talented jugadors available. The following table presents the payroll (in millions of dollars) for the 14 teams in Major League Baseball American League, like the total number of wins each in the 2008 season: Develop a regression model for predict the total number of wins based on the payroll of a team. According to the results of computer output, analyze how accurate the model. Use the model to predicir the number of wins a team payroll of $ 79 million.

      Teams                             Millions                          number of victories

    Yankees                              209.1                                         89

   Tigers                                   138.7                                        74

  Red Sox                                133.                                           95

  White Sox                             121.2                                          89

  Indians                                  79.0                                           81

   Orioles                                 67.2                                            68

  Oakland                                  48.0                                           75

Los Angeles                            119.2                                            100

Marines                                   118.0                                            61

Toronto                                   98.6                                              86

Minnesota                               62.2                                               88

Kansas City                            58.2                                                75

Tampa Bay                             43.8                                               97

Rangers                                   68.2                                              79

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