Exam 7: Sampling Distributions

The time spent commuting from home to work for all employees of a very large company has a normal distribution with a mean of 43.4 minutes and a standard deviation of 12.1 minutes.The probability,rounded to four decimal places,that the mean time spent commuting from home to work by a sample of 21 employees will be between 43.26 and 49.35 minutes is:

The mean age of all cars registered in the United States is 7.50 years.The mean age of a random sample of 1,000 cars is 6.9.The sampling error is:

A population contains 8 members.The total number of samples of size 4 that you can select (without replacement)from this population is:

The sampling distribution is the probability distribution of a:

If is less than or equal to 0.05,the standard deviation of the sampling distribution of the sample mean is equal to the population standard deviation:

Suppose the proportion of elements of a population that possess a certain characteristic is 0.62.Assuming ,the probability that the sample proportion for a sample of 120 elements drawn from this population is between .62 and .67,rounded to four decimal places,is approximately:

A class of 61 students has 15 seniors.The proportion of students in this class who are seniors,rounded to three decimal places,is:

When the sample size is greater than 1,the standard deviation of the sampling distribution of the sample means is always:

A population has a mean of 98.2 and a standard deviation of 25.2.Assuming ,the probability,rounded to four decimal places,that the sample mean of a sample of size 89 elements selected from this population will be between 91 and 97 is:

The daily sales at a convenience store have a mean of $1,297 and a standard deviation of $134.The mean of the sampling distribution of the mean sales of a sample of 17 days for this convenience store is:

For a continuous random variable x,the population mean and the population standard deviation are 139 and 9,respectively.You take a simple random sample of 36 elements from this population.The mean of the sampling distribution of the sample mean is:

A continuous random variable x has a left-skewed distribution with a mean of 155 and a standard deviation of 28.The sampling distribution of the sample mean for a sample of 75 elements taken from this population is:

Use the following to answer questions : Suppose that 6.5% or all persons are allergic to penicillin .A sample of 561 persons is selected. -The probability that less than 8% of persons in the sample of will be allergic to penicillin,rounded to four decimal places,is approximately:

A continuous random variable x has a right-skewed distribution with a mean of 72 and a standard deviation of 36.The sampling distribution of the sample mean for a sample of 100 elements has what mean and standard deviation?

For a sample from a normal distribution with standard deviation ,the standard deviation of the sampling distribution of the sample mean is /3.What is the size of the sample?

The mean age of all students at a university is 24 years.The mean age of a random sample of 100 students selected from this university is 23.6 years.The difference (23.6 - 24 = -0.4)is the:

Suppose the proportion of elements of a population that possess a certain characteristic is 0.34.Assuming ,the probability that the sample proportion for a sample of 472 elements drawn from this population is more than .33,rounded to four decimal places,is approximately:

The population distribution is the probability distribution of the:

A population has a normal distribution with a mean of 51.4 and a standard deviation of 8.4.Assuming ,the probability,rounded to four decimal places,that the sample mean of a sample of size 18 elements selected from this populations will be more than 51.15 is:

You select 15 people at random from a population of 10,000 and ask them how many movies they have rented in the past month.Their responses are: 4 0 6 0 8 3 7 6 5 0 1 4 2 9 5 You know that the mean number of movies rented in the past month by the population is 5.0.Assuming that you made no non-sampling errors,what is the sampling error for the mean?