1. A recent survey of local cell phone retailers showed that of all cell phones sold last month, 64% had a camera, 28% had a music player and 22% had both. Which of the following statements about cell phones sold last month is true?
|Having a camera and having a music player are mutually exclusive events.|
|The intersection of having a camera and having a music player is zero.|
|Having a camera and having a music player are independent events.|
|Having a camera and having a music player are disjoint events.|
|Having a camera and having a music player are not mutually exclusive events.|
1. The number of male babies in a sample of 10 randomly chosen babies is a:
|continuous random variable|
|Poisson random variable|
|binary random variable|
|binomial random variable|
1. Thirty work orders are selected from a filing cabinet containing 500 work order folders by choosing every 15th folder. Which sampling method is this?
|Simple random sample|
1. A sample of 250 people resulted in a confidence interval estimate for the proportion of people who believe that the federal government’s proposed tax increase is justified is between 0.14 and 0.20. Based on this information, what was the confidence level used in this estimation?
|Approximately 79 percent|
|Can’t be determined without knowing σ (sigma).|
1. A 99% confidence interval estimate can be interpreted to mean that
|if all possible samples are taken and confidence interval estimates are developed, 99% of them would include the true population mean somewhere within their interval.|
|we have 99% confidence that we have selected a sample whose interval does include the population mean.|
|both of the above.|
|none of the above.|
1. At the U.S. Open Tennis Championship a statistician keeps track of every serve that a player hits during the tournament. The statistician reported that the mean serve speed of a particular player was 105 miles per hour (mph) and the standard deviation of the serve speeds was 9 mph. If nothing is known about the shape of the distribution, give an interval that will contain the speeds of at least eight-ninths of the player’s serves.
|87 mph to 123 mph|
|132 mph to 159 mph|
|69 mph to 141 mph|
|78 mph to 132 mph|
1. Chebychev’s Theorem:
|applies to all samples|
|applies only to samples from a normal population|
|gives a narrower range of predictions than the Empirical Rule|
|is based on Sturges’ Rule for data classification|
1. A major department store chain is interested in estimating the average amount its credit card customers spent on their first visit to the chain’s new store in the mall. Fifteen credit card accounts were randomly sampled and analyzed with the following results: X (i.e. Xbar = $50.50) and s2(i.e. s squared = 400). Assuming the distribution of the amount spent on their first visit is approximately normal, what is the shape of the sampling distribution of the sample mean that will be used to create the desired confidence interval for μ (mew)?
|Approximately normal with a mean of $50.50|
|A standard normal distribution|
|A t distribution with 15 degrees of freedom|
|A t distribution with 14 degrees of freedom|
1. As part of an economics class project, students were asked to randomly select 500 New York Stock Exchange (NYSE) stocks from the Wall Street Journal. As part of the project, students were asked to summarize the current prices (also referred to as the closing price of the stock for a particular trading date) of the collected stocks using graphical and numerical techniques. Identify the sample of interest for this study.
|the current price (or closing price) of a NYSE stock|
|the entire set of stocks that are traded on the NYSE|
|a single stock traded on the NYSE|
|the 500 NYSE stocks that current prices were collected from|
1. A standardized test has a mean score of 500 points with a standard deviation of 100 points. Five students’ scores are shown below.
Which of the students have scores within two standard deviations of the mean?
|Adam, Beth, Ella|
|Adam, Beth, Carlos, Ella|
1. Suppose a sample of n = 50 items is drawn from a population of manufactured products and the weight, X, of each item is recorded. Prior experience has shown that the weight has a probability distribution with μ = 6 ounces (mew = 6 ounces) and σ = 2.5 ounces (sigma = 2.5 ounces). Which of the following is true about the sampling distribution of the sample mean if a sample of size 15 is selected?
|The mean of the sampling distribution is 6 ounces.|
|The standard deviation of the sampling distribution is 2.5 ounces.|
|The shape of the sample distribution is approximately normal.|
|All of the above are correct.|
1. A probability distribution is an equation that
|associates a particular probability of occurrence with each outcome in the sample space.|
|measures outcomes and assigns values of X to the simple events.|
|assigns a value to the variability in the sample space.|
|assigns a value to the center of the sample space.|
1. A survey was conducted to determine how people feel about the quality of programming available on television. Respondents were asked to rate the overall quality from 0 (no quality at all) to 100 (extremely good quality). The stem-and-leaf display of the data is shown below.
What percentage of the respondents rated overall television quality as very good (regarded as ratings of 80 and above)?