Exam 2- sampling distributions Flashcards Preview

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Flashcards in Exam 2- sampling distributions Deck (29):
0

Theoretical sampling distribution of x- bar is

The distribution of all x- bar values from all possible samples of the same size from the same population

1

Approximate sampling distribution of x- bar is

The distribution of x- bar values obtained from repeatedly taking SRSs of the same size from the same population

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Center

The mean of the sampling distribution of x- bar .... the mu....

Equals ..... Population mean

3

Mean =mu is valid for

All sample sizes and populations of all shapes

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Spread

The standard deviation of the sampling distribution of x- bar .....

Equals the standard deviation of the population divided by the square root of n

Valid for all sample sizes and population of all shapes

5

Shape

For non-normal population

Shape of sampling distribution of x-bar is approximately normal when n is large

6

Shape

For normal population

Shape of the sampling distribution if x- bar is exactly normal for any n

7

Mean ...... equals mu regardless of population shape or sample size

Exactly

8

Standard deviation of x- bar is always ..... Than the standard deviation of the population for samples of any size where ....

Less. n>1

9

Standard deviation of c- bar gets ....as n increases at rate ....

Smaller.... Square root of n

10

To cut standard deviation in half

Quadruple sample size

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Shape is normal if population is .....for any sample size

Normal

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Shape is approximately normal if we take a ...... ....... ....... from a non- normal population

Large random sample

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The population distribution of a variable is

The distribution of values of the variable among all the individuals in the population

14

The sampling distribution of a statistic is

The distribution of values taken by the statistic in all possible samples of the same size from the same population

15

The population distribution describes the ..... that make up the population

Individuals

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A sampling distribution describes how .... Varies in many samples from the population

Statistic

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What is distribution of random variable?

A list of all possible values of a variable together with how often each value occurs

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The probability of an event can be defined as

The fraction of time the event will occur if random phenomenon is related many time

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Central Limit Tgeorem

If you take a large SRS of size n from any population then the sampling distribution of x- bar is approximately not mail

20

The central limit theorem on x- bar requires

A large random sample

21

A correlation of r=0 indicates

That x and y are not linearly related

22

T/F probabilities on individuals can only be computed using the standard Normal table if the population is Normally distributed

True

23

What does the probability distribution of a random variable gives us?

All possible values if the random variable together with their probabilities

24

T/F because there is a probability assigned to each event, the probability model is correct

T

25

T/f because all probabilities are between zero and one, and because the sum of all probabilities is 1, the probability model is correct

True

26

The law of the large numbers refers to the .... Of a ..... Not to the sampling distribution of x- bar

Mean of a sample

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What does the Law of Large numbers tell us?

As sample size increases, the variable x-bar from a random sample gets closer and closer to mu

28

The mean x-bar of all possible samples will exactly equal to the population mean or would that a mean of a sampling distribution x-bar that would be equal mu?

The mean of the sampling distribution will equal mu