301 final

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1
Radom sample
a sample such that each member of the underlying population has an equal probability of being selected.
2
Population
data for every possible realveant case
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Confidence interval
a probabilistic statement about the likely value of a population charterisitc based on the observation in the sample
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Statistical significance
the relationship between two varribales is not due to radom chance and therefore exists in the boarder population
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Normal distburtion
a bell-shaped statistical distburtion that can be entirely charterzied by its mean and standard deviation
6
Standard error
the standard deviation of the sampling distribution of the sample mean.
Inference- the process of using what we know about a sample to make probabilistic statements about the border population
7
Difference of means
a method of bivarriate hypothesis testing that is appropriate for a categorical independent varribale and a continuous dependent varribale
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Correlation
measure of linear association between 2 continuous varribales
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Null hypothesis
predicts no relationship between the varribales
10
Omitted-varribale bias
specific type of bias that results from the failure to include a varribale that belongs in the regression model
11
Standardizing coefficients
regression coefficients such that the rise-over-run interpretation is expressed in standard deviation units of each varribale
12
Perfect multi-collineary
when there is an exact linear relationship between any two or more of a regressions models independent varriable
13
Dummy variable
a varribale that takes on one of two values usually 1 or zero
14
Probability
probablilty of an event is the number of times that event can occur relative to the total number of times any event can occur.
15
Properties of probablilty
The probability of an event is between 1 and 0
If the events can not occur simultaneously then p is the sum of the event probabilities
Probability that an event will not occur is 1-p(event)
Sum of probabilities from all possible events is 1
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Independence
two events are independent if the chance of one event occurring is not affected by the outcome of the other event.
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Rules of probability
1. Addition rule for mutually exclusive events -p. (outcome 1 or outcome 2) = p(outcome1) or p(outcome2)
2. Complement rule: -p(not outcome 1)= 1-p(outcome1)
3. Multiplication rule for independent outcomes- -p(outcome1 and outcome2)= p(outocme1 x P(outcome 2)
4. Multiplication rule for dependent events
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How to determine statistically significance
Perform a hypothesis test
Start with null hypothesis
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what assumptions to make when calculating proabablilty
There is no difference between treatments
What the probablility distrubution is
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If the null is 1 out of 20
reject it
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Statisicial inference
is the process of making probabilistic statements about a population characteristic based on our knowledge of the sample charterisitic.
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Outcome
result of radom observation
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Cross tabs
two categorical varribales
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T-test
binaryiv/ internalatio dv
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Regression
ways to measure an association between a and y where both values are at the intervalatio level of measurement
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Scatterplot
visual representation of the data on an x and y axis
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Five steps hypothesis test process
1. State the null hypothesis
2. Look at the data
3. Computing the “calculated” t
4. Calculate p-value
5. Draw a conclusion about the null hypothesis
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if the p-vlaue is less than .05
Reject the null hypothsis
29
if the p-vlaue is larger than .05
accept the null hypotheis
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