Exam 26: Statistics and Data Analysis

Do energy snack bars improve afternoon alertness? 100 factory workers were randomly assigned to two groups.One group ate energy snack bars at lunch and the other group ate placebo snack bars.At the afternoon break (approximately 1-1/2 hour after lunch), a significant increase in alertness was observed.Later analysis of the experiment results showed 87% of the participants exhibiting increased alertness were from the group which ate energy snack bars.

A company that processes wheat varies the milling time (short, medium and long) and bleaching (no bleaching and bleaching) and measure fiber content (gms/100 grams) of the resulting wheat product to determine the best combination for a desirable wheat product.Which of the following is true about this study?

A survey of investors finds that 60% use a full service brokerage firm to invest in stocks, 30% trade stocks online and 24% do both.The probability that an investor selected at random uses a full service brokerage firm or trades stocks online is ________________________ . One line space needed

The effectiveness of three brands of stain remover (EZ-Clean, SpotX, and OXYBoost) were rated (A = excellent to F = poor) by different groups of consumers.The appropriate nonparametric procedure to use to determine whether there differences in the perceived effectiveness among the three brands?

In listing a property, real estate agencies provides information on a number of variables.Which of the following variables related to property listings is categorical?

After the financial crisis of 2007/2008, the Dow Jones Industrial Average (DJIA) improved from a low of 7278 on March 20, 2009, to new records just a few years later.On August 8, 2011, the Dow dropped 634.8 points.A histogram of day-to-day changes in the DJIA looked like the histogram below.An accurate description of the distribution of changes in the DJIA is

Below is a histogram of prices for a sample homes recently sold in a metropolitan area in the southeastern region of the U.S. Histogram: Home Prices Which of the following statements is true?

Suppose a sample of 60 business majors revealed that the average time spent studying per week is 22 hours with a standard deviation of 4 hours.For one student reporting that he studies 16 hours per week, the corresponding z score is ________________________ .

College students were given three choices of pizza toppings and asked to choose one favorite.The following table shows the results. Given that a student's favorite topping is meat, what is the probability that the student is a junior? One line space needed

Suppose the time it takes for a purchasing agent to complete an online ordering process is normally distributed with a mean of 8 minutes and a standard deviation of 2 minutes.Suppose a random sample of 25 ordering processes is selected.What is the probability that the sample mean will be less than 7.5 minutes?

In a clinical trial, 780 participants suffering from high blood pressure were randomly assigned to one of three groups.Over a one-month period, the first group received a low dosage of an experimental drug, the second group received a high dosage of the drug, and the third group received a placebo.The diastolic blood pressure of each participant was measured at the beginning and at the end of the period and the change in blood pressure was recorded.Identify the levels of the factor.

IT staff for a large corporation has developed the following probability distribution for the number of calls requiring troubleshooting problems per day.Based on the distribution, the expected number of calls per day is

A recent survey of online shoppers asked them to indicate the primary reason they shop via the Internet.The table summarizes responses by reason and gender.What percent of males cite Convenience as the primary reason they shop online?

Absorption rates into the body are important considerations when manufacturing a generic version of a brand-name drug.A pharmacist read that the absorption rate into the body of a new generic drug (G) is the same as its brand-name counterpart (B).She has a researcher friend of hers run a small experiment to test Against the alternative )Which of the following would be a Type I error?

A farmer has increased his wheat production by about the same amount each year.His most useful predictive model is most probably ________________________ .

According to the residual plot for a linear regression model shown to the right, the linear model ________________________ .

The following payoff table (in thousands of dollars) considers three possible levels of demand in a housing complex.Using the maximax approach, the action taken should be to ________________________ .

Which of the following is not an assumption or condition that needs to be checked for a paired t-interval?

A manufacturer of cable wire periodically selects samples to monitor the process.A sample of ten wires is selected and the diameters (in cm.) are 0.493, 0.534, 0.527, 0.511, 0.565, 0.559, 0.519, 0.562, 0.551, and 0.530.The standard deviation is ________________________ .

Assume that a set of test scores in an Introduction to Finance class is normally distributed with a mean of 72 and a standard deviation of 8.Use the 68-95-99.7 rule to find the percentage of scores greater than 88.