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Business Statistics Final

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Which word is NOT part of the definition of descriptive statistics?
Predicting
If Gallup, Harris and other pollsters asked people to indicate their political party affiliation as Democrat, Republican or Independent, the data gathered would be an example of which scale of measurement?
Nominal
The order that runners finish in a race would be an example of continuous data.
False
Fifteen accounting majors had an average grade of 90 on a finance exam. Seven marketing majors averaged 85, while ten finance majors averaged 93 on the same exam. What is the weighted mean for the 32 students taking the exam?
89.84
Which one of the following is NOT an example of discrete data?
Number of miles between New York City and Chicago
What is the lowest level of measurement that a median can be computed?
Ordinal
The CIA World Factbook cited these numbers for the United States:
Birthrate is 14.14 births per 1,000 population

Average life expectancy for females in 80 years

Approximately 290 million persons residing in the US.

Each of these numbers is referred to as statistics
True
These are four levels of measurement-qualitative, quantitative, discrete, and continuous.
False
In a negatively skewed distribution, the mean is greater than the median.
False
A parameter is a measurable characteristic of a sample.
False
What is the range for a sample of March electric bills amounts for all-electric homes of similar sizes (to the nearest dollar): $212, $191, $176, $129, $106, $92, $108, $109, $103, $121, $175, and $194.
$120
A question in a market survey asks for a respondent's favorite car color. Which measure of central location should be used to summarize this question?
Mode
In a company, the standard deviation of the ages of female employees in six years and the standard deviation of the ages of male employees is ten years. These statistics indicate that the dispersion of age is greater for females than for males.
False
What type of variable is the number of gallons of gasoline pumped by a filling station during a day?
Continuous
A sample of the monthly amounts spent for food by families of four receiving food stamps approximates a symmetrical distribution. The sample mean is $150 and the standard deviation is $20. Using the Emperical Rule, about 95% of the monthly food expenditures are between what two amounts?
$110 and $190
The Union of Electrical Workers of America with 9,128 members polled 362 members about a new wage package that will be submitted to management. The population is the 362 members.
False
The terms descriptive statistics and inferential statistics can be used interchangeably.
False
For any data set, Chebyshev's Theorem estimates the proportion of observations that occurs within k standard deviations of the mean, where k is greater than 1.0.
True
According to the Emperical Rule, 95% of the observations lie within plus and minus 2.00 times (multiplied) the variance.
False
The general process of gathering, organizing, summarizing, analyzing, and interpreting data is called..
Statistics
Respondents were asked, "Do you now earn more than or less than you did five years ago?" What is this level of measurement?
Ordinal
A marketing research agency was hired to test a new DVD player. Consumers rated it outstanding, very good, fair or poor. The level of measurement for this experiment is ordinal.
True
Extremely high or low scores affect the value of the median.
False
What is the relationship among the mean, median, and mode in a symmetric distribution?
They are all equal
What is the relationship between the variance and the standard deviation?
Variance is the square of the standard deviation
The Pearson's coefficient of skewness is a measure of a distribution's symmetry.
True
The 50th percentile of a distribution is the same as the distribution's median.
True
A graphical method used to calculate joint and conditional probabilities is..
A tree diagram
A scatter diagram of sales versus production may be constructed by plotting the data on a graph labeled with sales on the Y-axis and production on the X-axis.
True
In a contingency table, we describe the relationship between
a two variables measured at the ordinal or nominal level
An experiment is an activity that is either observed or measured.
True
A tree diagram portrays outcomes that are mutually exclusive.
True
A study of the net sales of a sample of small corporations revealed that the mean net sales is $2.1 million, the median $2.4 million, the modal sales $2.6 million and the standard deviation of the distribution is $500,000. What is the Pearson's coefficient of skewness?
None of the above.
A dot plot shows the quartiles of a distribution.
False
When an event's probability depends on the likelihood of another event, the probability is a(n)..
Conditional probability
A dot plot shows..
The general shape of distribution.
An electronics firm sells four models of stereo receivers, three CD decks, and six speaker brands. When the four types of components are sold together, they form a "system." How many different systems can the electronics firm offer?
72
A relationship between two nominal variables is summarized by a contingency table.
True
Probabilities are important information when..
Using inferential statistics and predicting a future outcome.
When are two events mutually exclusive?
If one event occurs, then the other cannot.
What does the interquartile range describe?
the middle 50% of the observations.
The test scores for a class of 147 students are computed. What is the location of the test score associated with the third quartile?
111
The first card selected from a standard 52-card deck was a king. If it is NOT returned to the deck, what is the probability that a king will be drawn on the second selection?
3/51 or 0.0588
The probability of rolling a 3 or 2 on a single die is an example of conditional probability.
False
In a box plot, if a value is more than 1.5 times the interquartile range from the first or third quartile, the value is an outlier.
True
A coin is tossed four times. The probability is 1/4 or .25 that all four tosses will result in a head face up.
False
What does the complement rule state?
P(A)= 1-P(notA)
An individual can assign a subjective probability to an event based on the individual's knowledge about the event.
True
A weather forecaster announced that the probability of rain tomorrow is -1.0. We conclude there is no chance of rain.
False
In a scatter diagram, we describe the relationship between..
two variables measured at the interval or ratio level
A new car was put into production. It involved many assembly tasks. Each car was inspected at the end of the assembly line an the number of defects per unit was recorded. For the first 100 cars produced, there were 40 defective cars. Some of the cars had no defects; a few had one defect, and so on. The distribution of defects followed a Poisson distribution. Based on the first 100 produced, about how many out of very 1,000 cars assembled should have one or more defect?
About 330
The uniform probability distribution is symmetric about the mean and median.
True
An estimate of the population mean based on a large sample is less reliable than an estimate made using a small sample.
False
The mean of normal distribution is represented by σ.
False
For any uniform probability distribution, the mean and standard deviation can be computed by knowing the maximum and minimum values of the random variable.
True
Suppose a tire manufacturer wants to set a mileage guarantee on its new XB 70 tire. Tests revealed that the tire's mileage is normally distributed with a mean of 47,900 miles and a standard deviation of 2,050 miles. The manufacturer wants to set the guaranteed mileage so that no more than 5% of the times will have to be replaced. What guaranteed mileage should the manufacturer announce?
44,528
A group of statistics students decided to conduct a survey at their university to find the average amount of time students spend studying per week. Based on a simple random sample, they surveyed 144 students. The statistics showed that students studied an average of 20 hours per week with a standard deviation of 10 hours. What is the probability of finding a sample mean less than 18 hours?
0.0080
A random variable may be either discrete or continuous.
True
The total area within any continuous probability distribution is equal to 1.00.
True
All possible samples of size n are selected from a population and the mean of each sample is determined. What is the mean of the sample means?
Exactly the same as the population mean.
Two normal distribution are compared. One has a mean of 10 and a standard deviation has a mean of 10 and a standard deviation of 2. Which of the following is true?
The dispersions of the distributions are different.
When all the items in a population have an equal chance of being selected for a sample, the process is called....
Randomly Sampling
The binomial probability distributions is always negatively skewed.
False
What kind distribution are the binomial and Poisson distributions?
Discrete
Which of the following is the standard error of the mean?
σ/square root of n
A random variable represents the outcomes of an experiment.
True
What must you know to develop a binomial probability distribution?
Probability of success and number of trials.
The standard error of the mean is also called sampling error.
False
The mean score of a college entrance test is 500; the standard deviation is 75. The scores are normally distributed. What percent of the students scored below 320.
About 0.82
A national manufacturer of unattached garages discovered that the distribution of the lengths of time it takes two construction workers to erect the Red Barn model is normally distorted with a mean of 32 hours and a standard deviation of 2 hours. What percent of the garages take between 30-34 hours to erect?
68.26%
The probability and the number of automobiles lined up at a Lakeside Olds at opening time (7:30 am) for service are
2.85
A listing of all possible outcomes of an experiment and their corresponding probability of occurrence is called a
Probability distribution
In stratified random sampling, a population is divided into strata using naturally occurring geographic or other boundaries. Then strata are randomly is collected from each strata.
False
Based on the central limit theorem, sample error will decrease as sample size increases.
True
The Poisson probability distribution is a continuous probability distribution.
False
If we are testing for the difference between two population proportions, it is assumed that the two populations are approximately normal and have equal variances.
False
Hypothesis testing is a procedure that uses sample evidence and probability theory to decide whether to reject or fail to reject a hypothesis.
True
Two samples, one of size 14 and the second of size 13, are selected to test the difference between two population means. How many degrees of freedom are used to find the critical value? Assume the population standard deviations are equal.
25
If two independent samples of size 10 are used to test the difference between the means, the degrees of freedom for a t-statistic are 18.
False
A sample mean is the best point estimate of the
Population mean
A survey of an urban university (population of 25,450) showed that 870 of 1100 students sampled supported a fee increase to fund improvements to the student recreation center. Using the 95% level of confidence, what is the confidence interval for the proportion of students supporting the fee increase?
0.767, 0.814
The t distribution is a continuous distribution.
True
The null hypothesis is rejected when a p-value is greater than a stated significance level.
False
The mean weight of trucks traveling on a particular section of I-475 is not known. A state highway inspector needs an estimate of the mean. He selects a random sample of 49 trucks passing the weighing station and finds the mean weight is 15.8 tons. The population standard deviation is 3.8 tons. What is the 95 percent interval for the population mean?
14.7 and 16.9
Test at the 0.01 level the statement that 55% of those families who plan to purchase a vacation residence in Florida want a condominium. The null hypothesis is π = 0.55 and the alternate is . A random sample of 400 families who planned to buy a vacation residence revealed that 228 families want a condominium. What decision should be made regarding the null hypothesis?
Do not reject it
When sample sizes are less than 30, a test for the differences between two population means has n-1 degrees of freedom.
False
What are the two critical values for a two-tailed test with a 0.01 level of significance when n is large and the population standard deviation is known?
Above 2.58 and below -2.58
Accounting procedures allow a business to evaluate their inventory at LIFO (Last In First Out) or FIFO (First In First Out). A manufacturer evaluated its finished goods inventory (in $ thousands) for five products both
Mark 5.00 out of 5.00
Flag question
ways. Based on the following results, is LIFO more effective in keeping the value of his inventory lower?
4
A national manufacturer of ball bearings is
experimenting with two different processes for producing precision ball bearings. It is important that the diameters be as close as possible to an industry standard. The output from each process is sampled and the average error from the industry standard is calculated. The results are presented below.If we test the null hypothesis at the 1% level of significance, what is the decision?
Reject the null hypothesis and conclude the means are different.
To determine the size of a sample, the standard deviation of the population must be estimated by either taking a pilot survey or by approximating it based on knowledge of the population.
True
What is the probability of making a Type II error if the null hypothesis is actually true?
0
The level of significance is the risk of rejecting the null hypothesis when it is actually true.
True
If samples taken from two populations are not independent, then a test of paired differences is applied.
True
For a given confidence interval, what is the interpretation of a 96% confidence level?
Approximately 96 out of 100 such intervals would include the true value of the population parameter
Based on the Nielsen ratings, the local CBS affiliate claims its 11:00 PM newscast reaches 41% of the viewing audience in the area. In a survey of 100 viewers, 36% indicated that they watch the late evening news on this local CBS station. What is the p- value?
0.1539
An interval estimate is a range of values used to estimate a population parameter.
True
One assumption in testing a hypothesis about a proportion is that an outcome of an experiment can be classified into two mutually exclusive categories, namely, a success or a failure.
True
If the decision is to reject the null hypothesis of no difference between two population proportions at the 5% level of significance, what are the alternate hypothesis and rejection region?
z > 1.96 and z < -1.96
It is claimed that in a bushel of peaches less than ten percent are defective. A sample of 400 peaches is examined and 50 are found to be defective. If α = 0.025, what will be the decision?
Fail to reject the null and conclude the defects are not less than 10%
A point estimate is a single value used to estimate a population parameter.
True
A random sample of 30 executives from companies with assets over $1 million was selected and asked for their annual income and level of education. The ANOVA comparing the average income among three levels of education rejected the null hypothesis. The Mean Square Error (MSE) was 243.7. The following table summarized the results:

HS or Less: 7, 49
Undergrad: 11, 76.3
Master's: 12, 78.3

When comparing the mean annual incomes for executives with a High School education or less and Undergraduate Degree, the 95% confidence interval shows an interval of 11.7 to 42.7 for the difference. This result indicates that
Executives with an Undergraduate Degree earn significantly more than executives with a High School education or less.
What is the chart called when the paired data (the dependent and independent variables) are plotted?
Scatter diagram
When comparing the 95% confidence and prediction intervals for a given regression analysis,
The confidence interval is narrower than a prediction interval.
The coefficient of determination is the proportion of total variation in X that is explained by Y.
False
To employ ANOVA, the populations being studied must be approximately normally distributed.
True
Suppose that an automobile manufacturer designed a radically new lightweight engine and wants to recommend the grade of gasoline that will have the best fuel economy. The four grades are: regular, below regular, premium, and super premium. The test car made three trial runs on the test track using each of the four grades and the miles per gallon recorded. At the 0.05 level, what is the critical value of F used to test the hypothesis that the miles per gallon for each fuel is the same?

R: 39.31, 39.87, 39.87
BR:36.69, 40, 41.01
P: 38.99 40.02, 39.99
SP: 40.04, 39.89, 39.93
4.07
The test statistic used in ANOVA is Student's t.
False
In the regression equation, what does the letter "b" represent?
Slope of the line
An economist is interested in predicting the unemployment rate based on gross domestic product. Since the economist is interested in predicting unemployment, the independent variable is gross domestic product.
True
When analyzing a curvilinear relationship between dependent and independent variables, a transformation of the data is necessary.
True
If the correlation between two variables is close to one, the association is
Strong
Correlation analysis is a statistical technique used to measure the strength of the relationship between two variables.
True
What is the coefficient of determination?

Constant: -12.8094
Independent Variable: 2.179463
91.8%
Which statement is correct about the F distribution?
Cannot be negative
The alternate hypothesis used in ANOVA is

mean1=mean2=mean3
False
Two accounting professors decided to compare the variance of their grading procedures. To accomplish this they each graded the same 10 exams with the following results:

1: 79.3, 22.4
2: 82.1, 12.0
5.35
If the computed value of F is 0.99 and the critical value is 3.89, we would not reject the null hypothesis.
True
In the equation Y = a + bX, what is Y ?
Predicted value of Y, given a specific X value
Analysis of variance is used to
simultaneously compare several population means
In an ANOVA table, k represents the total number of sample observations and n represents the total number of treatments.
False
If a confidence interval for the difference between a pair of treatment means includes 0, then we fail to reject the null hypothesis that there is no difference in the pair of treatment means.
True
A manufacturer of automobile transmissions uses three different processes. Management ordered a study of the production costs to see if there is a difference among the three processes. A summary of the findings is shown below.

P1: 137, 10, 1893
P2: 108, 10, 1188
P3: 107, 10, 1175
Total: 352, 30, 4256
2.511
Explained variation equals total variation minus unexplained variation.
True
A t test is used to test the significance of the coefficient of correlation.
True
A hypothesis test is conducted at the .05 level of significance to test whether or not the population correlation is zero. If the sample consists of 25 observations and the correlation coefficient is 0.60, what is the computed value of the test statistic?
3.60
In chi-square applications, the sum of the differences between expected and observed frequencies must equal zero.
True
Multiple regression analysis is used when one independent variable is used to predict values of two or more dependent variables.
False
The chi-square goodness-of-fit test can be applied if
there are equal or unequal expected frequencies.
True
Which of the following is a characteristic of the F- distribution?
Positively skewed
How is the degree of association between a set of independent variables and a dependent variable measured?
Coefficient of multiple determination
A survey of the opinions of property owners about a street widening project was taken to determine whether the resulting opinion was related to the distance of front footage. A randomly selected sample of 100 property owners was contacted and the results are shown below.

For: 12, 35, 3
Undecided: 4, 5, 2
Against: 4, 30, 5

What is the expected frequency for people against the project and who have over 120 feet of property foot- frontage?
3.9
In a regression analysis, three independent variables are used in the equation based on a sample of forty observations. What are the degrees of freedom associated with the F-statistic?
3 and 36
Nonparametric tests of hypotheses, also called distribution free tests, require the population to be normally distributed.
False
For a contingency table, the expected frequency for a cell is found by dividing the row total by the grand total.
False
In multiple regression analysis, residuals (Y - Ŷ ) are used to:
Evaluate homoscedasticity
What is our decision for a goodness-of-fit test with a computed value of chi-square of 1.273 and a critical value of 13.388?
Do not reject the null hypothesis
Which of the following are correct statements regarding the goodness-of-fit test?
Data may be of nominal scale
The following correlations were computed as part of a multiple regression analysis that used education, job, and age to predict income. What is the table called?
Correlation matrix
In multiple regression analysis, a variable whose possible outcomes are coded as a "1" or a "0" is called a(n)
Dummy variable
In multiple regression analysis, a residual is the difference between the value of an independent variable and its corresponding dependent variable value.
False
Two chi-square distributions were plotted on the same chart. One distribution was for 3 degrees of freedom and the other was for 12 degrees of freedom. Which distribution would tend to approach a normal distribution?
12 degrees
The coefficient of multiple determination reports the strength of the association between a dependent variable and a set of independent variables.
True
The chi-square distribution can assume
only positive values
A correlation matrix can be used to assess multicollinearity between independent variables.
True
For the goodness-of-fit test, the use of the chi-square statistic would be permissible in the following problem.

Literate: 639, 642
Illiterate: 6, 3
False
In multiple regression analysis, a and b1 are sample statistics that estimate the population parameters, α and β1.
True
For a unit change in the first independent variable with other things being held constant, what change can be expected in the dependent variable in the multiple regression equation Y = 5.2 + 6.3X1 - 7.1X2?
+6.3
Which statistic is used to test hypotheses about individual regression coefficients?
T-statistic
The chi-square distribution is positively skewed.
True
A survey of the opinions of property owners about a street widening project was taken to determine whether the resulting opinion was related to the distance of front footage. A randomly selected sample of 100 property owners was contacted and the results are shown below.

For: 12, 35, 3
Undecided: 4, 5, 2
Against: 4, 30, 5

How many degrees of freedom are there?
4
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