stats 1350 unit 1 test review

A number that describes the population is

a perameter

Statistic

is a number that describes a sample. The value of a statistic is known when we have taken a sample but it can change from sample to sample.

Parameter

is a number that describes the population. Parameter is a fixed number, but in practice we dont know the actual value.

If no level of confidence is given in a confidence statement, then

it is assumed that the level of confidence is 95%

Cheshire High School announces the results of a survey— 31% of the senior class has an mp3 player. The survey was given to a random sample of 100 seniors. What is the population?

the senior class

The conclusion of a confidence statement always refers to

the population

Fill in the blank: Larger samples _____ than smaller samples

have less variability

If you want a smaller margin of error with the same confidence

increase the size of the sample

True or False: The size of the population determines the variability of the statistic from a random sample

False. Variability of a sample statistic depends on the size of the sample and not on the size of the population.

Variability

describes how spread out the values of the sample statistic are when we take many samples.

margin of error

phat=1/(square root)n

By increasing the size of a sample, we can

reduce variability

A good sampling method has

small bias, small variability

To reduce variability

take a larger sample

To reduce bias

use a random sample

To reduce bias, one needs to

use random sampling