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A student was interested in the cigarette smoking habits of college students and collected data from an unbiased random sample of students. The data is summarized in the following table: Why is the table NOT a frequency distribution? A. The […]

The annual income for a sample of 500 part-time students is normally distributed with a mean income of $30,000 and a standard deviation of $3,000. The income range that separates the top 25% from the lower 75% is __________. When […]

If the correlation coefficient between two variables, X and Y, equals zero, what can be said of the variables X and Y? A. The variables are not related. B. The variables are dependent on each other. C. The variables are […]

Sampling from a population may be preferred, because studying all the items in a population may be too ____________. What is the common purpose of a dot plot and a box plot? Answer: Both are used to illustrate the distribution […]

What must you know to develop a binomial probability distribution? A. The probability of success B. The probability of success and the number of trials C. The probability of success and the number of successes D. The number of trials […]

In multiple regression analysis, the ________ scale is used to measure a dummy variable. What-statistic is used to assess multicollinearity in multiple regression analysis? Answer: Variance inflation factor (VIF) The monthly consumer price index is called a(n) ______________. Answer: Statistic […]

In an ANOVA table for a multiple regression analysis, the regression mean square is __________. A. The treatment sum of squares divided by the regression degrees of freedom B. n – (k + 1) C. The regression sum of squares […]

A variable such as eye color is also referred to as a(n) _____________ variable. High school students were interested in a teacher’s claim that the longer the length of time (hours) that a student studies for a test, the higher […]

In one class, a statistics professor wants to compare grades on the first and second exams. This is an example of ________________ observations. For a contingency table test of independence, the formula to compute the degrees of freedom is_______________________________. Answer: […]

The regression equation is Ŷ = 29.29 – 0.96X, the sample size is 8, and the standard error of the slope is 0.22. What is the critical value to test the significance of the slope at the 0.01 significance level? […]

In a contingency table, we describe the relationship between ________. A. Two variables measured at the ordinal or nominal level B. Two variables, one measured as an ordinal variable and the other as a ratio variable C. Two variables measured […]

When testing the difference between two dependent population means, the test statistic is based on a ______________. A. Pooled variance B. Standard deviation of the differences C. Pooled proportion D. Sum of the population variances Answer: B. When the samples […]

For a data set, half of the observations are always greater than the ____. A. Median B. Mode C. Mean D. Standard deviation Answer: A. Half of the observations will be larger than the median and half smaller. This is […]

A study of interior designers’ opinions with respect to the most desirable primary color for executive offices showed that: What is the probability that a designer does not prefer red? A. 1.00 B. 0.77 C. 0.73 D. 0.23 Answer: B. […]

The major advantage of ordinal data over nominal data is that it allows for _________________. What are the two population parameters that specify the location and dispersion for the sampling distribution of the mean? Answer: µ, the population mean, and […]

A New York newspaper reported the average gasoline prices in four metropolitan areas and used a bar chart to illustrate the differences. What type of statistics was shown? What activities did the newspaper use to make the report? In a […]

Elly’s Hotdog Emporium is famous for its chilidogs. Elly’s latest sales indicate that 30% of the customers order their chilidogs with hot peppers. Suppose 15 customers are selected at random. What is the probability that between two and six people […]

Refer to the following distribution of ages: What is the class midpoint of the highest class? A. 54 B. 55 C. 64 D. 65 A random sample of 20 items is selected from a population. When computing a confidence interval […]

In multiple regression analysis, a dummy variable is ____________. A. An additional quantitative variable B. A nominal variable with three or more values C. A nominal variable with only two values D. A new regression coefficient The mean annual income […]

A personnel manager is concerned about absenteeism. She decides to sample employee records to determine if absenteeism is distributed evenly throughout the six-day workweek. The null hypothesis is: Absenteeism is distributed evenly throughout the week. Use the 0.01 level of […]

A telemarketing firm is monitoring the performance of its employees based on the number of sales per hour. One employee had the following sales for the last 19 hours. If we wanted to see if tossing a die (a cube […]

Which of the following is NOT necessary to determine how large a sample to select from a population? A. The level of confidence in estimating the population parameter B. The size of the population C. The maximum allowable error in […]

Records on a fleet of trucks reveal that the average life of a set of spark plugs is normally distributed with a mean of 22,100 miles. The fleet owner purchased 18 sets and found that the sample average life was […]

The shape of the F distribution is _____________________. A random sample of 20 female 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 […]

When dividing a population into subgroups so that a random sample from each subgroup can be collected, what type of sampling is used? A. Simple random sampling B. Systematic sampling C. Stratified random sampling D. Cluster sampling Answer: C. In […]

Accounting procedures allow a business to evaluate their inventory costs based on two methods: LIFO (Last In First Out) or FIFO (First In First Out). A manufacturer evaluated its finished goods inventory (in $000s) for five products with the LIFO […]

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. Answer: TRUE The variance inflation factor is used to select or remove independent variables […]

For any distribution, there are an equal number of values above and below the mean. Answer: FALSE There are an equal number of observations above and below the median. The central limit theorem states that if the sample size, n, […]

A frequency distribution for qualitative data has class limits. A statistics professor wants to compare grades in two different classes of the same course. This is an example of a paired sample. Answer: FALSE The professor must assume the two […]

The chi-square distribution is _____________. A. Positively skewed B. Negatively skewed C. Normally distributed D. Uniformly distributed A recent study of the relationship between social activity and education for a sample of corporate executives showed the following results. The appropriate […]

The regression equation is used to estimate a value of the dependent variable Y based on a selected value of the independent variable X. Answer: TRUE A p-value is the same as a stated significance level. Answer: FALSE A p-value […]

From past history, the scores on a statistics test are normally distributed with a mean score of 70 and a standard deviation of 5. To earn a “C” on the test, a student must be in the top 25% of […]

For hypotheses that compare two population means, what test statistic is used when the population standard deviations are unknown? The following frequency distribution shows the distribution of delivery times (in days) for swimstuff.com customer orders during the last month. How […]

Based on the central limit theorem, the sample mean can be used as a good estimator of the population mean, assuming that the size of the sample is sufficiently large. Answer: FALSE The results of the central limit theorem refer […]

To employ ANOVA, the populations being studied must be approximately normally distributed. 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 […]

An ANOVA has three sources of variation. They are _____, _____, and _____. We are interested in knowing if the following frequency distribution is normally distributed. The population mean and standard deviation of the data are 600 and 160, respectively. […]

Quartiles divide a distribution into ___________. A. 2 equal parts B. 4 equal parts C. 10 equal parts D. 100 equal parts Refer to the following distribution: What is the relative class frequency for the $25 up to $35 class? […]

Twenty-one executives in a large corporation were randomly selected to study the effect of several factors on annual salary (expressed in $000s). The factors selected were age, seniority, years of college, number of company divisions they had been exposed to, […]

A company is researching the effectiveness of a new website design to decrease the time to access a website. Five website users were randomly selected and their times (in seconds) to access the website with the old and new designs […]

For the following distribution of heights, what are the limits for the class with the greatest frequency? A. 64 and up to 70 B. 65 and 69 C. 65 and up to 70 D. 69.5 and 74.5 The mean of […]

A random sample of 20 female 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 […]

The arrival of customers at a service desk follows a Poisson distribution. If they arrive at a rate of four every five minutes, what is the probability that more than four customers arrive in a five-minute period? A confidence interval […]