Statistics (1028 problems)

A study investigated the perception of corporate ethical values among individuals specializing in marketing. Using and the following data (higher scores indicate higher ethical values), test for significant differences in perception among the three groups of specialists.

Five sections of AMDS 8437 took a test in July. The scores are provided in the data file that accompanies this test, with sections identified as A, B, C, D, E.

a. Determine whether the mean grades in the sections might be equal; if they are not equal, determine which one(s) is different. Show all steps in the test(s) that you do. Use a 5% level of significance for your test.

b. What assumptions underlie the test(s) that you performed? Do you think the data satisfy those assumptions? Do you think the test is valid?

Are some unskilled office jobs viewed as having more status than others? Suppose a study is conducted in which eight unskilled, unemployed people are interviewed. The people are asked to rate each of the five positions on a scale from 1 to 10 to indicate the status of the position, with 10 denoting most status and 1 denoting least status. The resulting data are given here. Use α = 0.05 and analyze the data

Five sections of AMDS 8437 took a test in July. The scores are provided in the data file that accompanies this test, with sections identified as A, B, C, D, E.

a. Determine whether the mean grades in the sections might be equal; if they are not equal, determine which one(s) is different. Show all steps in the test(s) that you do. Use a 5% level of significance for your test.

b. What assumptions underlie the test(s) that you performed? Do you think the data satisfy those assumptions? Do you think the test is valid?

Managers at all levels of an organization need adequate information to perform their respective task. One study investigated the effect the source has on the dissemination of information. In this particular study the sources of information were superior, peer and subordinate. In each case, a measure of dissemination was obtained, with higher values indicating greater dissemination of information. Using and the following data, test whether the source of information significantly affects dissemination. What is your conclusion, and what does it suggest about the use and dissemination of information?

A shoe retailer conducted a study to determine whether there is a difference in the number of pairs of shoes sold per day by stores according to the number of competitors within a 1-mile radius and the location of the store. The company researchers selected three types of stores for consideration in the study: stand-alone suburban stores, mall stores, and downtown stores. These stores vary in the numbers of competing stores within a 1-mile radius, which have been reduced to four categories: 0 competitors, 1 competitor, 2 competitors, and 3 or more competitors. Suppose the following data represent the number of pairs of shoes sold per day for each of these types of stores with the given number of competitors. Use α = 0.05 and analyze the data.

Choose any one of the following four statistical techniques. For your selected technique, create an original final exam problem, including any required data, which could be used to test BUS678 students’ knowledge. Be sure that the problem you create is truly original - do not copy a problem from a textbook or other source. Solve the problem using SPSS and send select portions of your SPSS output.

a. ANOVA
b. Regression

c. Correlation

d. Chi-square

If the null hypothesis is rejected use the Scheffe’ test when the sample sizes are unequal to test the differences between the means, and use the Tukey test when the sample sizes are equal. Test at the .05 significance level.

State the hypotheses and identify the claim, find the critical value(s), compute the test value, make the decision, summarize the results, and explain where the differences in means are.

The head of the English dept. wants to determine if the average number of students taking an English course differs depending upon the time of day that the court is being offered.

If the null hypothesis is rejected use the Scheffe’ test when the sample sizes are unequal to test the differences between the means, and use the Tukey test when the sample sizes are equal. Test at the .05 significance level.

State the hypotheses and identify the claim, find the critical value(s), compute the test value, make the decision, summarize the results, and explain where the differences in means are.

The head of the English dept. wants to determine if the average number of students taking an English course differs depending upon the time of day that the court is being offered.

Number of grams of fiber per serving for a random sample of 3 different kinds of foods is listed. It there sufficient evidence at the 0.05 level of significance to conclude that there is a difference in mean fiber content among breakfast cereals, fruits, and vegetable?

Numbers (in thousands) of farms per state found in 3 sections of the country are listed below. Test the claim at a=.05 that the mean number of farms is the same across these 3 geographic divisions.

Lengths (in feet) of a random sample of suspension bridges in the US, Europe, and Asia are shown. At a=.05, is there sufficient evidence to conclude that there is a difference in mean lengths?

Seventy five percent of married couples paid for their honeymoon themselves. You randomly select 20 married couples and ask if they paid for their honeymoon themselves. Find the probability that the number of couples who say they paid for their honeymoon themselves is:

a) Exactly ten

b) At least twelve

c) Less than twelve

For the tossing of a fair coin 100 times what is the B or bound of a confidence interval for 95%.

It has been estimated that 17.0% if mutual fund shareholders are retired persons. Assuming the population proportion to be π = 0.17, and that a simple random sample of 400 shareholders has been selected:

a) what is the expected value of p = the proportion of those in the sample who are retired?

b) what is the standard error of the sampling distribution of the proportion, p?

c) what is the probability that at least 20% of those in the sample will be retired?

d) what is the probability that between 15% and 25% of those in the sample will be retired?

According to the Bureau of Standards, 75 percent of all people have inner belly buttons, everyone else is an outer. Let the random variable x be the number of outers among 7 randomly selected persons.

Find the probability that exactly 2 of the 7 persons are outers.

Find the probability that no more than 6 of the 7 are outers.

Find the probability that none of the 7 is an outer.

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Bill must sell 3 more cars this month in order to meet his quota. Tonight he has after-dinner appointments with 5 prospective customers, each of whom happens to be interested in a different car. If he has a 30% chance of success with each customer, what is the probability the he will meet his quota by tomorrow morning/ Suppose that 3 of Bill’s customers were interested in the same car, and that they’ll go elsewhere if it has already been sold. Would it be appropriate to use the binomial distribution under these conditions? Why or why not?

A psychic network received telephone calls last year from over 1.5 million people. To test the credibility of the psychic network, an experiment was conducted and, 5 different cards were shuffled, and 1 is chosen at random. The psychic will then try to identify which card was drawn without seeing it. Assume that the experiment was repeated 45 times and that the results of any 2 experiments are independent of one another. If we assume that the psychic is fake, find the probability that they guess at least 3 correctly.

A steel pipe casting firm has purchased steel parts from a supplier for several years and has found that 10% of the parts must be returned because they are defective. An order of 10 parts is received.

a.) What is the probability that three or fewer of these parts are defective?

b.) What is the mean and standard deviation for the number of defective parts in orders of 10?

c.) What is the probability of receiving between 1 and 4 defective parts?

An Avon representative sells products to 25% of her customers each month. If she has 50 customers, what is the probability that she makes at most 7 sales?