Questions and Answers of Statistics For Business And Economics

GreenEnergy, a manufacturing company in Finland, wants to know the consumer satisfaction level for two products—A and B. A random sample of 12 consumers are invited to participate in a survey. The
Two different drugs for deliberating headaches are being analyzed for effectiveness. The analyst uses a random selection of 15 patients to test the first drug and 13 patients for the second drug. For
A newsletter rates mutual funds. Independent random samples of 12 funds with the highest rating and 12 funds with the lowest rating were chosen. The following figures are percentage rates of return
JW Intelligent proposed a new moisturizing cream that includes herbal essence as a key ingredient. A random sample of 15 women were selected for a pilot trial of the new product. The women used the
Petron has formulated a new chemical to be added in their petrol. To determine the effectiveness of the new formulated chemical, they recorded the amount of chemical had been added in the petrol (in
An investment company is going to make decision on which mobile app they are to invest from two different mobile application developments. The company accesses the ability on the two apps by
The accompanying table shows, for a random sample of 20 long-term-growth mutual funds, percentage return over a period of 12 months and total assets (in millions of pounds).a. Calculate the Spearman
Given a sequence 0.16, 0.27, 0.58, 0.63, 0.45, 0.21, 0.72, 0.87, 0.27, 0.15, 0.92, 0.85.a. How many runs for the sequence in total?b. What is the probability the number of run is less than 6?
A time series contains 10 and 16 observations. Determine the probability of the number of runs for the following.a. n = 10, P(R > 5)b. n = 16, P(4 < R < 7)
A time series contains 50 observations. What is the probability that the number of runs isa. No more than 13?b. Fewer than 15?c. Greater than 34?
Use the runs test to test for randomness the number of miles traveled per week for a car in three months. Week Distance (miles) 1 2 3 45 60 253 452 308 414 386 197 Week 7 8 a 9 10 11 12 Distance
The data file Euribor 12 Months shows an average annual interest rate of certain European banks over 18 consecutive years. Use the runs test to test this series for randomness.
The Tesla Stock Prices data file shows the closing price of Tesla’s stocks in the first day of each month for a period of 12 consecutive months. Test for randomness using the runs test.
On October 18, 2018, the fuel prices in Portugal went down after having risen to a five-year high the previous week. The Fuel Prices data file contains the price per liter of gasoline and of diesel,
Suppose the operations manager at a Honda service center conducts a survey on the level of satisfaction for the quality of workmanship based on the customer’s gender. A random sample of 200
Downsizing is one method companies may use in an attempt to reduce costs. Suppose that the following contingency table shows the number of layoffs in three manufacturing plants during the last 4
Test the hypothesisusing the following data.a.b.c.d. 2 2 Ho:c = c x y 2 2 H1:0 X V สง
Complete the following for the (x, y) pairs of data points (3,1), (4,5), (5,4), (7, 6), and (9, 8).a. Prepare a scatter plot of these data points.b. Compute b1.c. Compute b0.d. What is the equation
The following data give X, the price charged per piece of plywood, and Y, the quantity sold (in thousands).a. Prepare a scatter plot of these data points.b. Compute the covariance.c. Compute and
A critically important aspect of customer service at a supermarket is the waiting time at the checkout. Refer to the data file Supermarket, which contains total number of customers in the store (x)
As the new market manger for Blue Crunchies breakfast cereal, you are asked to estimate the demand for next month using regression analysis. Two months ago the target market had 20,000 families and
An agent for a real estate company in a large European city collected data, as shown in the following table, on the sizes (x in square feet) and monthly rents (y in euros) of a sample of eight
Suppose that we obtained an estimated equation for the regression of weekly sales of palm pilots and the price charged during the week. Interpret the constant b0 for the product brand manager.
Compute the coefficients for a least squares regression equation and write the equation, given the following sample statistics.a.b.c.d. x = 10, y = 50, Sx = 80, Sy = 75, Rxy = 0.4, n = 60
Refer to the following data, which contains the percentage change (X) in a stock market index over the first five trading days of the year and percentage change (Y) in the index over the whole
Let the sample regression line beand let x and y denote the sample means for the independent and dependent variables, respectively.a. Show thatb. Using the result in part a, show thatc. Using the
In a study it was shown that for a sample of 353 college faculty, the correlation was 0.11 between annual raises and teaching evaluations. What would be the coefficient of determination of a
Given the simple regression modeland the regression results that follow, test the null hypothesis that the slope coefficient is 0 versus the alternative hypothesis of greater than zero using
Use a simple regression model to test the hypothesis H0 : b1 = 0 versus H1 : b1 ≠ 0 with a = 0.05, given the following regression statistics.a. The sample size is 35, SST = 100,000, and the
A local wholesaler is interested in assessing the effect of the price of a premium bars of on the quantity sold. The results in the accompanying table on price, in pounds, and sales, in bars, were
Given a simple regression analysis, suppose that we have obtained a fitted regression modeland alsoFind the 90% confidence interval and 90% prediction interval for the point where x = 12. ŷ₁ = 11
Given a simple regression analysis, suppose that we have obtained a fitted regression modeland alsoFind the 95% confidence interval and 95% prediction interval for the point where x = 11. ŷi = 14 +
Given a simple regression analysis, suppose that we have obtained a fitted regression modeland alsoFind the 95% confidence interval and 95% prediction interval for the point where x = 17. ŷ₁ = 22
Given a simple regression analysis, suppose that we have obtained a fitted regression modeland alsoFind the 95% confidence interval and 95% prediction interval for the point where x = 17. ŷi = 8 +
A sample of 10 blue-collar employees at a production plant was taken. Each employee was asked to assess their job satisfaction (x) on a scale of 1 to 10. In addition, the numbers of days absent (y)
The data file Trading Stocks shows percentage changes (xi) in a stock market over the first five trading days of each of 11 years and also the corresponding percentage changes (yi) in the index over
Using a 0.10 level of significance, test the null hypothesis H0 : ρ = 0 versus H1 : ρ ≠ 0 given the following.a. A sample correlation of 0.46 for a random sample of size n = 25.b. A sample
In a study of 33 countries, the sample correlation between an index of political turmoil and the infant mortality rate was 0.28. At the 0.05 level, test the null hypothesis of no correlation between
The accompanying table and the data file Dow Jones show percentage changes (xi) in the Dow Jones index over the first five trading days of each of 13 years and also the corresponding percentage
As part of a process to build a new banking portfolio, you have been asked to determine the beta coefficients for two Dutch banking and financial services companies, ING and Rabobank. Data for this
If a regression of the yield per acre of corn on the quantity of fertilizer used is estimated using fertilizer quantities in the range typically used by farmers, the slope of the estimated regression
In a random sample of 545 accountants engaged in preparing county operating budgets for use in planning and control, 117 indicated that estimates of cash flow were the most difficult element of the
Din Tai Fung, Taiwan, specializes in xiaolongbao (steamed dumplings) and Chinese cuisine. It has a number of clients that use their process for producing exotic Huaiyang dinners for customers in the
The student council at a university wants to estimate the percentage of the student body that supports a change being considered in the academic calendar of the university for the next academic year.
Mary Arnold wants to use the results of a random sample market survey to seek strong evidence that her brand of breakfast cereal has more than 20% of the total market. Formulate the null and
The board of a national central bank is meeting to decide if it should reduce interest rates in order to prevent deflation. State the null and alternative hypotheses regarding deflation that the
The 2000 presidential election in the United States was very close, and the decision came down to the results of the presidential voting in the state of Florida. The election was finally decided in
Test the hypotheses using a random sample of n = 36, a probability of Type I error equal to 0.05, and the following sample statistics.a. x = 108; s = 20b. x = 104; s = 10c. x = 96; s = 10d. x = 95; s
Here we have the complement of Exercise 9.5. The 2000 presidential election in the United States was very close, and the decision came down to the results of the presidential voting in the state of
Test the hypotheses using a random sample of n = 49, a probability of Type I error equal to 0.05, and the following sample statistics.a. x = 108; s = 20b. x = 104; s = 10c. x = 96; s = 10d. x = 95; s
A random sample of n = 25 is obtained from a population with variance σ2, and the sample mean is computed. Test the null hypothesis H0 : μ = 120 versus the alternative hypothesis H1 : μ
A manufacturer of cereals claims that the contents of boxes sold weigh on average at least 20 ounces. The distribution of weight is known to be normal, with a standard deviation of 0.5 ounce. A
A company selling licenses for new e-commerce computer software advertises that firms using this software obtain, on average during the first year, a yield of 10% on their initial investments. A
Kongsberg Maritime, a Norwegian technology enterprise, receives a shipment of batteries from Grenland Energy, a battery manufacturer in Skien, Norway, and tests a random sample of nine before
A pharmaceutical manufacturer is concerned that the impurity concentration in pills should not exceed 3%. It is known that from a particular production run impurity concentrations follow a normal
A process that produces bottles of shampoo, when operating correctly, produces bottles whose contents weigh, on average, 20 ounces. A random sample of nine bottles from a single production run
A random sample of 1,556 employees at Boris&Boris, Inc., Russia, has been asked to attend an ethics workshop. The employees were asked to rate the following statement from a scale from 1
A statistics instructor is interested in the ability of students to assess the difficulty of a test they have taken. This test was taken by a large group of students, and the average score was 80.3.
A random sample of 171 employees was asked to rate, on a scale from 1 (not important) to 5 (extremely important), health benefits as a job characteristic. The sample mean rating was 2.07, and the
In a random sample of 472 owners of small businesses that had gone into bankruptcy, 352 reported conducting no marketing studies prior to opening the business. Test the hypothesis that at most 70% of
In a random sample of 468 export managers in the United Kingdom, 90 members indicated some measure of disagreement with this statement: Globalization is more than an economic trade system—instead
Of a random sample of 214 auditors, 125 indicated some measure of agreement that cash flow is an important indication of profitability. Test at the 5% significance level against a two-sided
A random sample of 10 students contains the following observations, in hours, for time spent studying in the week before final exams:Assume that the population distribution is normal.a. Find the
Of a random sample of 172 elementary school educators, 118 said that parental support was the most important source of a child’s success. Test the hypothesis that parental support is the most
At the 5% significance level, test the hypothesesusing the following results from the following random samples.a. s2 = 145; n = 21b. s = 156; n = 30 c. s2 = 144; n = 26d. s2 = 165; n = 26
Assume a random sample of 185 business faculty members from the Vlerick Business School, Belgium, was asked if there should be a required foreign language course for business majors. Of the sample
A company that receives shipments of batteries tests a random sample of 16 of them before agreeing to take a shipment. The company is concerned that the true mean lifetime for all batteries in the
In a random sample of 1,099 adults in a certain country, 21.3% of the sample members indicated some measure of disagreement with this statement: Globalization is more than an economic trade
When operating normally, a manufacturing process produces sheets of paper for which the mean weight of the active ingredient is 5 grams, and the standard deviation is 0.025 gram. For a random sample
Lantmännen Cerealia, Stockholm, has asked you to study the variability of the weights of cereal bags produced in plant 2, located in Norway. The package weights are known to be normally distributed.
Suppose you just got a job located at the center of your city and now need to decide where to live. If you live close to the location, your commute will be shorter. If you live in the outskirts, your
A study was conducted to analyze the status of patients at a particular hospital in Finland. The ICU data file contains information on adult patients who were alive when admitted to the hospital’s
You have accepted a job in Taiwan and want optimize your commuting costs and rental costs. You are in the process of finalizing an apartment. You are informed that a house in Taiwan is considered
A process produces cable for the local telephone company. When the process is operating correctly, cable diameter follows a normal distribution with mean 1.8 inches and standard deviation 0.03 inch.
A study at the hospital in Finland concluded that the percentage of patients admitted with a bone fracture was less than 15%. State whether the conclusions of the study are still valid. You are then
According to the WHO Global Ambient Air Quality Database, the most impacted are populations in low-income regions, with 97% of cities in low- and middle- income countries with more than 100,000
The ICU data file contains information of a study made with adult patients that were alive when admitted in the Intensive Care Unit (ICU) of a hospital. Variable descriptions are located in the
Use the ICU data file and test if individuals aged up to 40 years old are likely to suffer from complications due to high SBP. What can you conclude about individuals older than 40? Variable
The ICU data file contains information of a study made with adult patients that were admitted in the Intensive Care Unit (ICU) of a hospital. Variable descriptions are located in the chapter
Test the hypothesesusing the following statistics from random samples.a.b.c.d.e. Ho: Px H₁: P, Py = 0 P
The ICU data file contains information of a study made with adult patients that were admitted to the Intensive Care Unit (ICU) of a hospital. Variable descriptions are located in the chapter
The ICU data file contains information from a study conducted on adult patients that were admitted to the Intensive Care Unit (ICU) of a hospital. Variable descriptions are located in the chapter
In a study comparing banks in two countries, a sample of 148 matched pairs of banks was formed. Each pair contained one bank from the Netherlands and one from Croatia. The pairings were made in such
An agency in Belgium offers preparation courses for a graduate school admissions test to students. As part of an experiment to evaluate the merits of the course, 40 students were chosen and divided
Auditors might be helped in determining the chances of fraud if they carefully measure cash flow. To evaluate if auditors might be helped in determining the chances of fraud if they carefully measure
Small-business telephone users were surveyed 6 months after access to carriers other than Carrier A became available for wide-area telephone service. Of a random sample of 240 Carrier A users, 133
Employees of a building materials chain in Monaco who were facing a shutdown were surveyed on a prospective employee ownership plan. Some employees pledged €10,000 to this plan, putting up €1,000
Of a random sample of 455 high-quality investment equity options, 203 had less than 30% debt. Of an independent random sample of 205 high-risk investment equity options, 183 had less than 30% debt.
Of a random sample of 1,000 people in Denmark, 500 had a positive attitude toward TV salespeople. Of an independent random sample of 1,600 people in France, 730 had a positive attitude toward TV
A professor claims that exam scores for non-accounting majors are more variable than for accounting majors. Random samples of 30 non-accounting majors and 30 accounting majors are taken from a final
To evaluate if auditors might be helped in determining the chances of fraud if they carefully measure cash flow, samples of midlevel auditors from CPA firms were asked to indicate the chance of
A statistician tests the null hypothesis that the proportion of men favoring a tax reform proposal is the same as the proportion of women. Based on sample data, the null hypothesis is rejected at the
Independent random samples of bachelor’s and master’s degree holders in statistics, whose initial job was with a major actuarial firm and who subsequently moved to an insurance company, were
Of a random sample of 80 health insurance firms in Europe, 63 did public relations in-house, as did 52 of an independent random sample of 80 casualty insurance firms. Find and interpret the p-value
A study was conducted to determine if there was a difference in humor content in British and American trade magazine advertisements. In an independent random sample of 300 American trade magazine
Guardian Wealth Management, a financial planning company in Geneva, Switzerland, buys and sells a large number of stocks routinely for the various accounts that it manages. Portfolio manager Anne
BNP Paribas, France, buys and sells a large number of stocks routinely for the various accounts that it manages. Portfolio manager Louise Abou has asked for your assistance in the analysis of the
PowerChina, a Chinese construction company, is building a large, new retail center at the Chengdu Industrial Development Zone, Sichuan. Yao Minhao, one of the project managers, requests that a pile
An investment portfolio in Finland specializes in pulp and paper stocks and includes two of them. One is Valmet (mean 0.1; standard deviation .025), and it accounts for 40% of the portfolio shares.
Suppose you have a traditional die with 6 faces numbered from 1 to 6.a. What is the population distribution of numbers on the die?b. Determine the sampling distribution of the sample mean of the

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