Exam 7: Sampling Distributions

The sample mean is an unbiased estimate of the population mean.

The Central Limit Theorem is considered powerful in statistics because it works for any population distribution provided the sample size is sufficiently large and the population mean,and standard deviation are known.

SCENARIO 7-5 According to an article,19% of the entire population in a developing country has high-speed access to the Internet.Random samples of size 200 are selected from the country's population. -Referring to Scenario 7-5,among all the random samples of size 200,_____% will have less than 20% who have high-speed access to the Internet.

Major league baseball salaries averaged $3.26 million with a standard deviation of $1.2 million in a certain year in the past.Suppose a sample of 100 major league players was taken.Find the approximate probability that the mean salary of the 100 players was no more than $3.0 million.

SCENARIO 7-2 The mean selling price of new homes in a small town over a year was $115,000.The population standard deviation was $25,000.A random sample of 100 new home sales from this city was taken. -Referring to Scenario 7-2,what is the probability that the sample mean selling price was between $113,000 and $117,000?

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?

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

A study at a college in the west coast reveals that,historically,45% of the students are minority students.If random samples of size 75 are selected,80% of the samples will have less than _____ % of minority students.

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.