Exam 7: Sampling Distributions and Sampling

$\text { The standard deviation of the sampling distributionof a sample proportionis } \sqrt { \frac { ? ( 1 - ? ) } { n } } \text { where } u \text { is }$ the population proportion.

TABLE 7-5 The manager of the customer service division of a major consumer electronics company is interested in determining whether the customers who have purchased a videocassette recorder made by the company over the past 12 months are satisfied with their products. -Referring to Table 7-5, if a customer survey questionnaire is included in all the videocassette recorders made and sold by the company over the past 12 months, this method of collecting data will most like suffer from

The sample proportion is an unbiased estimate of the population proportion.

A population frame for a survey contains a listing of 72,345 names. Using a table of random numbers, how many digits will the code numbers for each member of your population contain?

TABLE 7-7 Online customer service is a key element to successful online retailing. According to a marketing survey, 37.5% of online customers take advantage of the online customer service. Random samples of 200 customers are selected. -Referring to Table 7-7, _____ % of the samples are likely to have less than 37.5% who take advantage of online customer service.

TABLE 7-7 Online customer service is a key element to successful online retailing. According to a marketing survey, 37.5% of online customers take advantage of the online customer service. Random samples of 200 customers are selected. -Referring to Table 7-7, the standard error of all possible sample proportions is _____.

$\text { The standarderrorof the sampling distributionof a sample proportionis } \sqrt { \frac { p ( 1 - p ) } { n } } \text { where } p \text { is the }$ sample proportion.

A study at a college in the west coast reveals that, historically, 45% of their students are minority students. If a random sample of size 75 is selected, the probability is _____that more than half of the students in the sample will be minority students.

If the amount of gasoline purchased per car at a large service station has a population mean of $15 and a population standard deviation of $4 and it is assumed that the amount of gasoline purchased per car is symmetric, there is approximately a 68.26% chance that a random sample of 16 cars will have a sample mean between $14 and $16.

A manufacturer of power tools claims that the average amount of time required to assemble their top-of-the-line table saw is 80 minutes with a standard deviation of 40 minutes. Suppose a random sample of 64 purchasers of this table saw is taken. The standard deviation of the sampling distribution of the sample mean is ____minutes.

A study at a college in the west coast reveals that, historically, 45% of their students are minority students. If random samples of size 75 are selected, 80% of the samples will have less than _____% of minority students.

The standard error of the mean

Referring to Table 7-4, the standard deviation of all the sample proportions of customers who will make a purchase after visiting the web site is _____ .

The sampling process begins by locating appropriate data sources called _____.

TABLE 7-6 According to an article, 19% of the entire U.S. population have high-speed access to the Internet. Random samples of size 200 are selected from the U.S. population. -Referring to Table 7-6, the standard error of all the sample proportions is____ .

For distributions such as the normal distribution, the arithmetic mean is considered more stable from sample to sample than other measures of central tendency.

Using different frames to generate data can lead to totally different conclusions.

A study at a college in the west coast reveals that, historically, 45% of their students are minority students. If random samples of size 75 are selected, the standard error of the proportions of students in the samples who are minority students is____ .

The Central Limit Theorem ensures that the sampling distribution of the sample mean approaches normal as the sample size increases.

To gather opinions on the efficacy of U.S. foreign policies, a sample of 50 faculty members is selected from the pool of university professors who have taught political science at the graduate level. This is an example of a judgment sample.