W. Bowen and T. Finegan (1965) published a paper titled "Labor Force Participation and Unemployment." In that paper they estimated the following regression using a data set of 78 cities:
The standard errors for the OLS coefficient estimates are in parentheses. (Note: You might have already noticed that many research papers choose to report the standard errors for the coefficients instead of the tstatistics.)
Where:
Li = percent labor force participation (males age 25 to 54) in the ith city
Ui = percent unemployment rate in the ith city
Ei = average earnings (hundreds of dollar/year) in the ith city
Ii = average other income(hundreds of dollars/year) in the ith city
Si = average schooling completed (years) in the ith city
Ci = percent of the labor force that is nonwhite in the ith city
Di = a dummy equal to 1 if the city is in the South and 0 otherwise
A. Calculate the tstatistics for each of the coefficients assuming the null hypotheses are that the independent variables are not correlated with the dependent variable.
B. For which of the independent variables can you reject the null hypothesis at the 5% level of confidence?
Textbook authors and publishers work very hard to minimize the number of errors in a text. However, some errors are unavoidable. Mr. J. A. Carmen, statistics editor, reports that the mean number of errors per chapter is 0.8. What is the probability that there are less than 2 errors in a particular chapter?
Find P25 for the following data: 2 6 3 4 2 1 2 0 1 3 6 3
You are given the following frequency distribution for the number of errors 10 students made in a test
Errors Frequency
02 14
35 13
68 11
911 8
1214 9
Find: a. mean b. variance c. standard deviation.
An air traffic control error is said to occur when planes come too close to one another. The following data represent the number of air traffic control errors for a random sample of regions around the US for fiscal years 1996 and 2000.
a. Compute the sample mean number of errors in 1996 and 2000
b. Compute the median numb
What are the characteristics of a standard normal distribution? Can two distributions with the same mean and different standard distributions be considered normal? How might you determine if a distribution is normal from its graphical representation?
A software company finds that the average number of errors in its software per 1000 lines of code is 4 with standard deviation equal to 0.5. Use the 689599.7 rule to calculate the following values:
a)Almost all (99.7%) 1000 lines of code contain a number of errors that varies in what range of values?
b)The percentage of
A researcher measures the following scores for a group of people. The X variable is the number of errors on a math test, and the Y variable is the person's level of satisfaction with his/her performance.
A.) With such ratio scores, what should the researcher conclude about this relationship?
B.) How well will he be able
The standard error of the mean:
A. is never larger than the standard deviation of the population
B. decreases as the sample size increases
C. measures the varability of the mean from sample to sample
D. All of the above
1. You are given the following frequency distribution for the number of errors that students made in a test
Errors Frequency
02 13
35 17
68 0
911 16
1214 3
Find the mean, variance, and standard deviation.
2. You are given the following data.
x y
2 11
3 19
4 4
5 19
5 2
7 14
7 6
Find:

Use the empirical rule of statistics to explain the percentage of data values in a normal distribution that fall within:
a) 1 standard deviation of the mean
b) 2 standard deviations of the mean
c) 3 standard deviations of the mean