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