quiz 7

Question 1

the way a sample is selected is called the ___________or ____________

Answer 1

SAMPLING PLAN, EXPERIMENTAL DESIGN

Question 2

a commonly used sampling plan in which every sample of size n has the same chance of being selected.

Answer 2

Simple Random Sampling

Question 3

A simple random sample can also be called a _____

Answer 3

random sample

Question 4

when the data already exists and you are just picking the random data for sample

Answer 4

observational study

Question 5

Most sample_____, in which info is gathered in a questionnaire, fall into this category, obervational study

Answer 5

surveys

Question 6

when population consists of 2 or more subpopulations, called ______, a sampling plan that ensures that each subpopulations is represented in the sample is called a ________ random sample

Answer 6

strata, stratified

Question 7

Stratified random sampling involves selecting a simple random sample from each of a given # of subpops. or strata

Answer 7

true

Question 8

A cluster sample is a simple random sample of clusters from the available _____ in the populations

Answer 8

clusters

Question 9

Sometimes the population to be sampled is _____ such as an alphabetical list of people with driver’s license, then we can use a _________ random sample

Answer 9

ordered, systematic

Question 10

A ________ systematic randon sample involves the random selection of one of the first K elements in an ordered population and then the systematic selection of every Kth element after that

Answer 10

1 of K

Question 11

a sample that can be easily and simply obtained without random selection

Answer 11

convenience sample

Question 12

a convenience sample is non-random and can not be used for making inferences

Answer 12

true

Question 13

when you select a random sample, the numerical descriptive measure you calculated from the sample are called…

Answer 13

statistics`

Question 14

These statistics vary or change from sample to sample, that is they are _______

Answer 14

random variables

Question 15

The probability distribution for statistics are called _______ distributions

Answer 15

sampling

Question 16

One important statistical theorem that describes the sampling distribution of statistics that are sums of averages is…

Answer 16

central limit theorem

Question 17

Under rather general conditions, this theorem states that sums and means of random samples of measurements drawn from a population tend to have an approximately______ distribution

Answer 17

normal

Question 18

The spread of the distribution is slowly decreasing as the sample size n increases (true or false)

Answer 18

trueeeee

Question 19

CLT- if random samples of n observations are drawn from a non-normal population with finite mean and standard deviation, then , when n is large, the sample mean follows a normal distribution with mean ____ and standard deviation

Answer 19

ϻ, σ/√(n)

Question 20

The CLT can be restated to apply to the sum of the sample measurements which as n becomes large, also has an approximate _______ distribution with mean _________ and standard deviation ______

Answer 20

normal, n x ϻ, √(n) x σ

Question 21

the standard deviation of a statistic used as an estimator of a population parameter is also called _______ of the estimator (SE), because it refers to the _______ of the estimator

Answer 21

standard error, error

Question 22

SE( sample mean)=

Answer 22

σ/√(n)

Question 23

estimating or predicting the value of the parameter

Answer 23

estimation

Question 24

making a decision about the value of a parameter based on a preconceived idea about what the value might be

Answer 24

hypothesis test

Question 25

an ______ is a rule usually expressed as a formula that tells us how to calculate an estimate based on info in a sample

Answer 25

estimator

Question 26

a single # is calculated to estimate population parameter

Answer 26

point estimator

Question 27

2 numbers are calculated to form an interval within which the parameter is expected to lie withing

Answer 27

interval estimator

Question 28

a point estimator is said to be ____ if the mean of its distribution is the true value of the parameter being estimated, otherwise, the estimator is said to be ____

Answer 28

unbiased, biased

Question 29

the _____ ( as measured by the variance) of the estimator’s sampling distribution should be as small as possible

Answer 29

spread ( better if spread is more concentrated around true value)

Question 30

The distance between an estimate and the true value of the parameter is called the ______ of estimation

Answer 30

error

Question 31

the probability that the true value falls into interval is called the ________. (1- α) x 100%

Answer 31

confidence

Question 32

If the sample size is large enough, then CLT applies so we can work with ________ distributions

Answer 32

normal

Question 33

1-α is the probability that the interval covers the true value. The smaller the α is, the _____ interval is

Answer 33

wider

Question 34

if n increases, the interval is getting _____. This is because large n means more information, therefore less uncertainty

Answer 34

narrower