Exam 9: Sampling Distributions

The amount of bleach a machine pours into bottles has a mean of 50 ounces with a standard deviation of 0.25 ounces.We take a random sample of 36 bottles filled by this machine.The sampling distribution of the sample mean has a mean of 50 ounces.

If two populations are normally distributed, the sampling distribution of the difference in the sample means, , is:

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

Retirees A sample of 50 retirees is drawn at random from a normal population whose mean age and standard deviation are 75 and 6 years, respectively. -(Retirees Narrative} Describe the shape of the sampling distribution of the sample mean in this case.

CFO's Salary Suppose that the starting salaries of female CFO's have a positively skewed distribution with mean of $56,000 and a standard deviation of $12,000.The starting salaries of male CFO's are positively skewed with a mean of $50,000 and a standard deviation of $10,000.A random sample of 50 female CFO's and a random sample of 40 male CFO's are selected. -{CFO's Salary Narrative} Find the standard error of the sample mean difference.

The standard deviation of is also called the:

An infinite population has a mean of 40 and a standard deviation of 15.A sample of size 100 is taken at random from this population.The standard error of the sample mean equals:

Barack Obama Bill Clinton, the former President of the United States, believes that the proportion of voters who will vote for Barack Obama in the year 2012 presidential elections is 0.65.A sample of 500 voters is selected at random. -{Barack Obama Narrative} What is the probability that the number of voters in the sample who will vote for Barack Obama in the year 2012 is between 340 and 350?

Graduate Internships The chairman of the Biology department in a certain college believes that 70% of the department's graduate internships are given to international students.A random sample of 50 graduate interns is taken. -{Graduate Internships Narrative} What is the probability that the sample proportion is within.05 of the population proportion p?

The Central Limit Theorem states that, if a random sample of size n is drawn from a population, then the sampling distribution of the sample mean :

Which of the following statements about the sampling distribution of is NOT true?

The standard deviation of is also called the ____________________ of the sample proportion.

The width of the sampling distribution of gets ____________________ as the sample size increases.

Heights of Men The heights of men in the USA are normally distributed with a mean of 68 inches and a standard deviation of 4 inches. -{Heights of Men Narrative} A random sample of five men is selected.What is the probability that the sample mean is greater than 70 inches?

If all possible samples of size n are drawn from a population, the probability distribution of the sample mean is called the:

Two samples are selected independently from two normal populations and the mean and standard error of the sampling distribution of are 32 and 38.72, respectively.Calculate P( > 0).

If all possible samples of size n are drawn from a normal population, the probability distribution of the sample mean is an normal distribution.

CFO's Salary Suppose that the starting salaries of female CFO's have a positively skewed distribution with mean of $56,000 and a standard deviation of $12,000.The starting salaries of male CFO's are positively skewed with a mean of $50,000 and a standard deviation of $10,000.A random sample of 50 female CFO's and a random sample of 40 male CFO's are selected. -{CFO's Salary Narrative} What is the sampling distribution of the sample mean difference ? Explain.

The expected value of the sampling distribution of the sample mean equals the population mean $\mu$ :

A sample of size 25 is selected from a population of size 500.The finite population correction is needed to find the standard error of .