Exam 7: Sampling and Sampling Distributions

Exhibit 7-1 A random sample of 121 bottles of cologne showed an average content of 4 ounces. It is known that the standard deviation of the contents i.e., of the population) is 0.22 ounces. -Refer to Exhibit 7-1. The point estimate of the mean content of the bottles is

A sample of 24 observations is taken from a population that has 150 elements. The sampling distribution of is

How many simple random samples of size 3 can be selected from a population of size 7?

The sample statistic, such as , s, or , that provides the point estimate of the population parameter is known as

Four hundred people were asked whether gun laws should be more stringent. Three hundred said "yes," and 100 said "no." The point estimate of the proportion in the population who will respond "yes" is

A simple random sample of 28 observations was taken from a large population. The sample mean equaled 50. Fifty is a

The following information was collected from a simple random sample of a population. 16 19 18 17 20 18 The point estimate of the population standard deviation is

Stratified random sampling is a method of selecting a sample in which

Random samples of size 525 are taken from an infinite population whose population proportion is 0.3. The standard deviation of the sample proportions i.e., the standard error of the proportion) is

The average lifetime of a light bulb is 3,000 hours with a standard deviation of 696 hours. A simple random sample of 36 bulbs is taken. a. What are the expected value, standard deviation, and shape of the sampling distribution of ? b. What is the probability that the average life in the sample will be between 2,670.56 and 2,809.76 hours? c. What is the probability that the average life in the sample will be greater than 3,219.24 hours? d. What is the probability that the average life in the sample will be less than 3,180.96 hours?

A random sample of 150 people was taken from a very large population. Ninety of the people in the sample were female. The standard error of the proportion is

A population characteristic, such as a population mean, is called

Which of the following sampling methods does not lead to probability samples?

A sample of 400 observations will be taken from an infinite population. The population proportion equals 0.8. The probability that the sample proportion will be greater than 0.83 is

Exhibit 7-2 A random sample of 10 examination papers in a course, which was given on a pass or fail basis, showed the following scores. Paper Number Grade Status 1 65 Pass 2 87 Pass 3 92 Pass 4 35 Fail 5 79 Pass 6 100 Pass 7 48 Fail 8 74 Pass 9 79 Pass 10 91 Pass -Refer to Exhibit 7-2. The point estimate for the variance of the population is

A simple random sample of 6 recent graduates revealed the following information about their weekly incomes. Graduates Weekly Income \ 250 270 285 240 255 290 a. What is the expected value of the average weekly income of all the recent graduates? b. What is the expected value of the standard deviation for the population?

How many different samples of size 3 can be taken from a finite population of size 10?

A sample statistic, such as a sample mean, is known as

Doubling the size of the sample will

The expected value of the random variable is