ICQ 3 group 4

The Central Limit Theorem states that the sampling distribution of the sample mean is approximately normal under certain conditions. Which of the following is a necessary condition for the Central Limit Theorem to be used?

• The sample size must be large (e.g., at least 30).

• The population size must be large (e.g., at least 30)

• The population from which we are sampling must be normally distributed.

• The population from which we are sampling must not be normally distributed.

The Central Limit Theorem is important in statistics because _____.

• For any sample size, it says the sampling distribution of the sample mean is approximately normal

• For any population, it says the sampling distribution of the sample mean is approximately normal, regardless of the sample size

• For a large sample size, it says the sampling distribution of the sample mean is approximately normal, regardless of the population

• For a large sample size, it says the population is approximately normal

A 70% confidence interval for a population mean is determined to be 800 to 900. If the confidence is increased to 90% confidence while the sample statistics and sample size remain the same, the confidence interval

• becomes wider

• becomes narrower

• does not change

A research group wishes to estimate the margin of error in the mean amount of time (in hours) that members of a fitness center spend exercising each week. the sample size is 64, and from the previous historical data, the standard deviation is 2.2. calculate the margin of error with 95% confidence level.

• 60

• 3

• 0.53

• 0.9

A Parks Department employee wants to know if sulphur infused paint is more durable than non-sulphur infused paint. She has 43 park benches painted with sulphur paint and has 43 park benches painted with non-sulphur paint. What kind of study is this?

• experimental

• observational

• survey

• double blind

A teacher splits her classes up by grades A,B and C achieved by the students. She then randomly picks 3 students from each group to do a survey. What kind of sampling is this?

• Stratified

• Cluster

• Systematic

• Biased