Exam 7: Sampling Distributions

To use the normal distribution to approximate the binomial distribution,we need __________and _________ to be at least 5.

A statistic calculated from a sample is used to estimate the corresponding

The amount of pyridoxine (in grams)per multiple vitamin is normally distributed with $\mu$ = 110 grams and $\sigma$ = 25 grams.A sample of 25 vitamins is to be selected. -What is the probability that the sample mean will be greater than 100 grams?

Which of the following statements about the sampling distribution of the sample mean is incorrect?

Instruction 7.6 Online customer service is a key element to successful online retailing. According to a marketing survey, 37.5% of online customers take advantage of the online customer service. Random samples of 200 customers are selected. -Referring to Instruction 7.6,the population mean of all possible sample proportions is _________

The fact that the sample means are less variable than the population data can be observed from the standard error of the mean.

A manufacturer of power tools claims that the average amount of time required to assemble their top-of-the-line table saw is 80 minutes with a standard deviation of 40 minutes. -Suppose a random sample of 64 purchasers of this table saw is taken.So,95% of the sample means based on samples of size 64 will be between ___________and _____________.

A study at a university in New South Wales reveals that,historically,45% of their 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.

The amount of time required for an oil and filter change on a car is normally distributed with a mean of 45 minutes and a standard deviation of 10 minutes.A random sample of 16 cars is selected -What is the probability that the sample mean is between 45 and 52 minutes?

The owner of a fish market has an assistant who has determined that the weights of rainbow trout are normally distributed,with mean of 3.2 kilograms and standard deviation of 0.8 kilogram. -If a sample of 16 fish is taken,what would the standard error of the mean weight equal?

A sample that does not provide a good representation of the population from which it was collected is referred to as a(n)_____ sample.

Why is the Central Limit Theorem so important to the study of sampling distributions?

Instruction 7.5 According to an article, 19% of the entire Australian population have high-speed access to the Internet. Random samples of size 200 are selected from the Australian population. -Referring to Instruction 7.5,among all the random samples of size 200,90% will have less than _________ % who have high-speed access to the Internet.

At a computer manufacturing company,the actual size of computer chips is normally distributed with a mean of 1 cm and a standard deviation of 0.1 cm.A random sample of 12 computer chips is taken. -Above what value do 2.5% of the sample means fall?

At a computer manufacturing company,the actual size of computer chips is normally distributed with a mean of 1 cm and a standard deviation of 0.1 cm.A random sample of 12 computer chips is taken. -What is the probability that the sample mean will be between 0.99 and 1.01 cm?

Instruction 7.2 The mean selling price of new homes in a country town over a year was $115,000. The population standard deviation was $25,000. A random sample of 100 new home sales from this town was taken. -Referring to Instruction 7.2,what is the probability that the sample mean selling price was more than $110,000?

The amount of bleach a machine pours into bottles has a mean of 1080 grams with a standard deviation of 4.5 grams.Suppose we take a random sample of 36 bottles filled by this machine. -The sampling distribution of the sample mean has a mean of 1080.

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

The standard error of the mean for a sample of 100 is 30.In order to cut the standard error of the mean to 15,we would

Instruction 7.6 Online customer service is a key element to successful online retailing. According to a marketing survey, 37.5% of online customers take advantage of the online customer service. Random samples of 200 customers are selected. -Referring to Instruction 7.6,________ % of the samples are likely to have between 35% and 40% who take advantage of online customer service.