Exam 7: Sampling and Sampling Distributions

The mean of the sampling distribution of a sample proportion is the population proportion, π.

The standard deviation of the sampling distribution of a sample proportion is where π is the population proportion.

Measurement error can become an ethical issue when an interviewer purposely guides the responses in a particular direction.

Which of the following sampling methods will more likely be susceptible to ethical violation when used to form conclusions about the entire population?

The question "How many times have you abused your spouse in the last 6 months?" will most likely result in nonresponse error.

The question: "How much did you earn last year rounded to the nearest hundreds of dollars?" will most likely result in measurement error.

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 more than 30% who have high-speed access to the Internet.

The amount of time it takes to complete an examination has a left skewed distribution with a mean of 65 minutes and a standard deviation of 8 minutes. If 64 students were randomly sampled, the probability that the sample mean of the sampled students exceeds 71 minutes is approximately 0.

If the amount of gasoline purchased per car at a large service station has a population mean of 15 gallons and a population standard deviation of 4 gallons 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 gallons.

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

TABLE 7-2 The time spent studying by students in the week before final exams follows a normal distribution with a standard deviation of 8 hours. A random sample of 4 students was taken in order to estimate the mean study time for the population of all students. -Referring to Table 7-2, what is the probability that the sample mean is more than 3 hours below the population mean?

When participants are allowed to self-select into the sample, you have a nonprobability sample.

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. The sampling distribution of the sample mean has a mean of 36 oz.

If the expected value of a sample statistic is equal to the parameter it is estimating, then we call that sample statistic

As the sample size increases, the standard error of the mean increases.

Coverage error results in a ________.

TABLE 7-1 The manager of the customer service division of a major consumer electronics company is interested in determining whether the customers who have purchased a DVD player made by the company over the past 12 months are satisfied with their products. -Referring to Table 7-1, which of the following questions in the survey will not likely induce a measurement error?

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

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. -A study at a college in the west coast reveals that, historically, 45% of the students are minority students. If a random sample of size 75 is selected, the probability is ________ that between 30% and 50% of the students in the sample will be minority students.

Major league baseball salaries averaged $3.26 million with a standard deviation of $1.2 million in a recent year. Suppose a sample of 100 major league players was taken. Find the approximate probability that the mean salary of the 100 players exceeded $4.0 million.