Sampling Distributions Review

• the standard deviation of a population

• the standard deviation of a sample

• the mean of a population

• the mean of a sample

Portly Polls is taking a poll on whether twins have eaten a sandwich for lunch. Is this a proportion problem or a situation involving means? Why?

• means -- we are looking at averages

• means -- we are looking for a yes/no

• proportion -- we are looking for a yes/no

• proportion -- we are looking at averages

Picky Polls is taking a poll on how many TVs twins own on average. Is this a proportion problem or a situation involving means? Why?

• means -- we are looking at averages

• means -- we are looking for a yes/no

• proportion -- we are looking at averages

• proportion -- we are looking for a yes/no

When are you looking at a mean based problem?

• When the collected information consists of two options (yes and no for example)

• When the questions consist of numbers

• When the collected information consists of numbers

• When the questions consist of two options (yes and no for example)

How can you check to see if your sample of size n is large enough to apply the Central Limit Theorem?

• n ≤ 10

• n ≤ 30

• n ≥ 10

• n ≥ 30

Increasing the sample size of an opinion poll will reduce the

• bias of the estimates made from the data collected in the poll.
• variability of the estimates made from the data collected in the poll.
• variability of opinions in the sample.
• variability of opinions in the population.

A statistic is unbiased if...

• the value of the statistic from any sample is NOT equal to the parameter
• The value of the statistic from any sample IS equal to the parameter
• The mean of the sampling distribution is NOT equal to the true value of the parameter
• The mean of the sampling distribution IS equal to the value of the population mean

A random sample of female college students has a mean height of 64.5 inches, which is greater than the 63 inch mean height of all adult American women. 63 inches is a

• Sample

• Population

• Statistic

• Parameter

At a particular college, 78% of all students are receiving some kind of financial aid.The school newspaper selects a random sample of 100 students and 72% of the respondents say they are receiving some sort of financial aid. Which of the following is true?

•  78% is a population and 72% is a sample.
• 72% is a population and 78% is a sample
• 78% is a parameter and 72% is a statistic
• 72% is a parameter and 78% is a statistic

A company has 500 employees and wants to evaluate a proportion using the distribution of sample proportions and normal curve. Under which circumstance will they be able to do this?

• n = 80, p = .2

• n = 40, p = .2

• n = 40, p = .9

• n = 30, p = .4