Exam 7: Sampling and Sampling Distributions

An unbiased estimator will have a value,on average across samples,equal to the population parameter value.

Coverage error can become an ethical issue if a particular group is intentionally excluded from the frame.

TABLE 7-6 According to an article,19% of the entire population in a developing country have high-speed access to the Internet.Random samples of size 200 are selected from the country's population. -Referring to Table 7-6,the standard error of all the sample proportions is ________.

TABLE 7-6 According to an article,19% of the entire population in a developing country have high-speed access to the Internet.Random samples of size 200 are selected from the country's population. -Referring to Table 7-6,among all the random samples of size 200,________ % will have between 9% and 29% who have high-speed access to the Internet.

If the population distribution is unknown,in most cases the sampling distribution of the mean can be approximated by the normal distribution if the samples contain at least 30 observations.

TABLE 7-5 According to a survey,only 15% of customers who visited the website of a major retail store made a purchase.Random samples of size 50 are selected. -Referring to Table 7-5,90% of the samples will have less than what percentage of customers who will make a purchase after visiting the website?

TABLE 7-6 According to an article,19% of the entire population in a developing country have high-speed access to the Internet.Random samples of size 200 are selected from the country's population. -Referring to Table 7-6,among all the random samples of size 200,________ % will have between 14% and 24% who have high-speed access to the Internet.

In inferential statistics,the standard error of the sample mean assesses the uncertainty or error of estimation.

Suppose μ = 80 and σ = 20 for a population.In a sample where n = 100 is randomly taken,95% of all possible sample means will fall above 76.71.

TABLE 7-6 According to an article,19% of the entire population in a developing country have high-speed access to the Internet.Random samples of size 200 are selected from the country's population. -Referring to Table 7-6,the population mean of all the sample proportions is ________.

As the sample size increases,the effect of an extreme value on the sample mean becomes smaller.

Which of the following types of samples can you use if you want to make valid statistical inferences from a sample to a population?

Which of the following sampling methods will more likely be susceptible to ethical violation?

Measurement error can become an ethical issue when a survey sponsor chooses leading questions that guide the responses in a particular direction.

The amount of time required for an oil and filter change on an automobile is normally distributed with a mean of 45 minutes and a standard deviation of 10 minutes.A random sample of 16 cars is selected.What is the standard error of the mean?

A manufacturer of power tools claims that the mean 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 probability that the sample mean will be less than 82 minutes is ________.

A sample is always a good representation of the target population.

The amount of bleach a machine pours into bottles has a mean of 36 oz.with a standard deviation of 0.15 oz.Suppose we take a random sample of 36 bottles filled by this machine.So,the middle 95% of the sample means based on samples of size 36 will be between ________ and ________.

The amount of time required for an oil and filter change on an automobile is normally distributed with a mean of 45 minutes and a standard deviation of 10 minutes.A random sample of 16 cars is selected.95% of all sample means will fall between what two values?

The professor of a business statistics class wanted to find out the mean amount of time per week her students spent studying for the class.She divided the fifty students on her roster into ten groups starting from the first student on the roster.The first student was randomly selected from the first group.Then every tenth student was selected from the remaining students.This is an example of a cluster sample.