To measure the effect of a storewide sales campaign on non-sale items, the research director took a random sample of 13 pairs of stores that were matched according to average weekly sales volume. One store of each pair (the experimental group) was exposed to the sales campaign, and the other member of the pair (the control) gro
Part I: In this exericse, we have a box of paint cans for a project kit. The box contains 100 bottles in total, with the following colors: yellow, black, green, blue. We will randomly select 15 bottles from the box and count how many are yellow.
1. Since we have determined the optimal sample size, n, using a three variable formula. Fill in the following table listing the three variables and specify the effect on n (either + or -) of increasing and decreasing each variable, one at a time. VARIABLE EFFECT of INCREASE EFFECT of DECREASE 2. Given a Chi-Squar
The owner of a local night club has recently surveyed a random sample of n=250 customers of the club. She would now like to determine whether or not the mean age of her customers is over 30. If so, she plans to alter the entertainment to appeal to an older crowd. If not, no entertainment changes will be made. If she wants to be
Please see the attached file for full question. Two independent (unrelated) sample groups of parents and grandparents were recruited. A total of 105 young adult parents, between the ages of 21 and 40 years, participated in this study. A total of 105 middle-aged and older grandparents, ranging in age from 36 to 84 years (M = 6
Microsoft Excel was used on a set of data involving the number of parasites found on 46 Monarch butterflies captured in Pismo Beach State Park. A biologist wants to know if the mean number of parasites per butterfly is over 20. She will make her decision using a test with a level of significance of 0.10. The following informat
An entrepreneur is considering the purchase of a coin-operated laundry. The present owner claims that over the past 5 years, the average daily revenue was $675 with a standard deviation of $75. A sample of 30 days reveals a daily average revenue of $625. If you were to test the null hypothesis that the daily average revenue w
Please see attached Chapter 9, exercise number 12 12. The American Sugar Producers Association wants to estimate the mean yearly sugar consumption. A sample of 16 people reveals the mean yearly consumption to be 60 pounds with a standard deviation of 20 pounds. a. What is the value of the population mean? 20 What is the
In recent year, of the 109,857 arrest fro federal offenses, 29.1% were for drug offenses. Use a .01 significance level to test the claim that the drug offense rate is equal to 30%. What is the value of the test statistic?
Hypothesis Testing - Heather Carielli is a former student who earned a master degree at the University of Arkansas. When she randomly selected 16 new text books in the college book store she found that they had prices with a mean of $70.41 and a standard deviation of $19.70. Is there sufficient evidence to warrant rejection of a claim in the college catalog that the mean price of the textbook at the college is less than $75.00? use .05 significance level. Accept or the reject the null?
Heather Carielli is a former student who earned a master degree at the University of Arkansas. When she randomly selected 16 new text books in the college book store she found that they had prices with a mean of $70.41 and a standard deviation of $19.70. Is there sufficient evidence to warrant rejection of a claim in the colle
A data set includes the heights of parents of 20 males. If the difference in height for each set of parents is found by subtracting the mother's height from the father's height, the result is a list of 20 values with a mean of 4.4 inches and a standard deviation of 4.2 inches. Use a .01 significance level to test the claim the
In a Sgallop poll of 1012 randomly selected adults, 9% said cloning of humans should be allowed. Use a .05 significance level to the test claim that less than 10% of all adults said that cloning should be allowed. Accept or reject the null hypothesis?
The web-based company Oh Baby! Gifts has a goal of processing 95 percent of its orders on the same day they are received. If 485 out of the next 500 orders are processed on the same day, would this prove that they are exceeding their goal, using a = .025?
Faced with rising fax costs, a firm issued a guideline that transmissions of 10 pages or more should be sent by 2-day mail instead. Exceptions are allowed, but they want the average to be 10 or below. The firm examined 35 randomly chosen fax transmissions during the next year, yielding a sample mean of 14.44 with a standard devi
Surveys have been widely used by politicians around the world as a way of monitoring the opinions of the electorate. Six months ago, a survey was undertaken to determine the degree of support for a national party leader. Of a sample of 1,100, 56% indicated that they would vote for this politician. This month, another survey o
I am having trouble with some stats problems. Can you assist me? Thanks in advance The NPC, Inc. is a large mail order company that ships men's shirts all over the United States and Canada. They ship a large number of packages from their warehouse in Delta, Ohio. Their goal is to have 95 percent of the shipments delivered
Surveys have been widely used by politicians around the world as a way of monitoring the opinions of the electorate. Six months ago, a survey was undertaken to determine the degree of support for a national party leader. Of a sample of 1,100, 56% indicated that they would vote for this politician. This month, another survey of 8
An operations manager who supervises an assembly line has been experiencing problems with the sequencing of jobs. The problem is that bottlenecks are occurring because of the inconsistency of sequential operations. He decides to conduct an experiment wherein two different methods are used to complete the same task. He measure
Use a 10% significance level. Every month a clothing store conducts an inventory and calculates the losses due to theft. The store would like to reduce these losses and is considering two methods. The first is to hire a security guard, and the second is to install cameras. To help decide which method to choose, they hired a
In random samples of 12 from each of two normal populations, we found the following statistics: Xbar1 = 74 S1= 18 Xbar2 = 71 S2 =16 a) Test with α= .05 to determine whether we can infer that the population means differ. b) Repeat part a increasing the standard deviations to S1= 210 and S2 =198. c) Describe what
A U.S. Department of Justice report included the claim that "in spouse murder cases, wife defendants were less likely to be convicted than husband defendants." Sample data consisted of 277 convictions among 318 husband defendants and 155 convictions among 222 wife defendants. Test the stated claim. Assume Aplha = 0.05. What are
Inspection of student data generated during pre/post treatment surveys shows that among 10 subjects, 7 had higher scores after an experimental treatment, 2 had lower scores, and 1 score did not change. Using the traditional method of hypothesis testing, we need to determine if the experimental course has any effect. Use an alpha
Assume that the random variable is normally distributed. A courier service advertises that its average delivery time is less than 6 hours for local deliveries. A random sample of times for 12 deliveries to an address across town was recorded. These data are shown here. Is this sufficient evidence to support the courier's adv
A machine that produces ball bearings is set so that the average diameter is .50 inch. A sample of 10 ball bearings was measured with the results shown here. Assuming that the standard deviation is .05 inch, can we conclude at the 5% significance level that the mean diameter is not .50 inch? .48 .50 .49 .52 .53 .48 .49 .47 .
A business student claims that on average an MBA student is required to prepare more than five cases per week. To examine the claim, a statistics professor asks a random sample of ten MBA students to report the number of cases they prepare weekly. The results are exhibited here. Can the professor conclude at the 5% significan
To see if young men ages 9 - 17 spend more or less than the average of $24.44 per shopping trip, the manager surveyed 33 young men and found the average amount spent was $22.67. The pop std us $3.70. At alpha 0.2, can it be concluded the average amount spent by the young men is not equal to $24.44 Perform appropriate hypoth
A survey by the national institute of health asked a random sample of young adults (aged 19 to 25), "Where do you live now? That is, where do you stay most often?" We earlier compared the proportions of men and women who lived with their parents. Here now is the full two-way table (omitting a few who refused to answer and one w
The color of a fabric depends on the dye used and also how the dye is applied. This matters to clothing manufacturers, who want the color of the fabric to be just right. The study discussed in the previous exercise went on to dye fabric made of ramie with the same "procion blue" dye applied in two different ways. Here are the
Publishing scientific papers online is fast, and the papers can be long. Publishing in a paper journal means that the paper will live forever in libraries. The British Medical Journal combines the two: it prints short and readable versions, with longer versions available online. Is this OK with authors? The journal asked a r
A random digit dialing telephone survey of 880 drivers asked, "Recalling the last ten traffic lights you drove through, how many of them were red when you entered the intersectinos?" Of the 880 respondents, 171 admitted that at least one light had been red. a)Give a 95% confidence interval for the proportion of all drivers who