In regards to a measurement scale, a data set for residential houses defining pool or no pool would be:
Mean and Median
Which of the following is a measurement of the central therom?
Between Mean and Median, which one is more affected by outliers
decreasing in the marginal (per unit) output production and increasing of single factor, while all other amounts stay the same
Break even point
Indifferent, when forcasted revenue exactly equals the estimated total costs
Reducing Sampling Error
This gives you a better chance for accuracy with avoiding sampling error
(ALL) Sampling is more cost effective Sampling is more timely Sampling is more practical
When attempting to accurately depict group variable as a whole, take small subsets to make statistical inferences rather than try to capture the entirety of the observable data. WHY?
Define the objective of the survey
For the scope of this course, when creating a survey the first thing one should do is?
Stratified Sampling (levels)
The type of sampling in which elements within the population are divided into groups and a randomly selected sample are taken from those groups to analyze?
In general one can expect to see more ____ bias in subjects in which individuals have strong opinions? (religion, politics, sports)
Events are ____ _____ if they cannot happen at the same time. (Either/or)
Standard and Poors
Example of a data vendor?
Class rank (freshmen, soph, ect) coded as 1-2-3-4 is a _____ variable
What variable is the example GPA?
The measurement scale for the variable class rank (Quant)
taking the 115th person on every 12th page of the phone book is an example of what sampling?
would a randomly selected group of 50 undergraduate GSU students be a sample or population?
the difference between xbar and u when sampling is done corretly is referred to as?
Simple Random Sample
Sample where everyone in the pop. is in the sampling frame and has the same prob. of being selected?
A measure or count of deviations from the mean of a group data
What central location measurement is more affected by deviation
uses the same base units as the original data
S.D. uses the same base units, we take the square root of variance to compute deviation.
Why would we prefer using Standard deviation as a measurement over variance?
constitute the entire range of possibilities
Is conceptual metric that has no single, fixed value
Suppose you are applying to a busa. school post undergrad, and the AVG GMAT score range of most applicants is 550-650. This range is what kind of variable?
Say you take the GMAT and you know you made in between 550-650. What type of variable is your raw score.
Each observation is dependent upon previous observations
Which of the following is a qualification for a distribution to be considered binomial?
Time sensitive with only two possible outcomes
0 and 1
The standard normal distribution has a mean of __ and a standard deviation of ___ .
Continuous Asymptotic to the axis
Standard deviation is always ___ as the sample size increases
Assume Normal Distribution
The central limit theorem allows us to ____ given an adequate SRS sample
number of deviations some value is above or below the mean
discrete with only 2 possible outcomes per trial
What happens to the SE if n is increased?
x is discrete random variable
it takes on different numerical value based on chance
Only two outcomes are possible
probability distribution that is used to estimate population parameters when the sample size is small and/or when the population variance is not known
Degrees of freedom
refer to the number of independent observations or events in a set of data as
Number of Independent observations
Subtracting one from the sample size (n-1)
What dist. always has a mean of 0
T Test: Margin of Error
our appropriate T score multiplied by our standard error
I take a SRS of 49 and find that the sample mean is 350 and sample deviation is 45. I want to be 95% that the mean are within the certain value. What is Alpha?
I take a SRS of 49 and find that the mean is 350, deviation is 45. how many independent observations do we have?
Standard Error for proportions
What is equal to the square root of (P*(1-P)?N)
Standard Error Decreases
in both proportions and mans for a sample statistic, what happens to our standard error is the number of observations increases
a T value at alpha=.05 is always the same (TorF)
At a given level of Alpha, we have a t value of (t.05=2.5), what then is (t.95) for the same number of independent observations
Mutually Exclusive Collectively exhaustive
In hypothesis testing our two forms (Ho and Ha) are:
out of out Null (Ho) and Alternative(ha) which do we consider to initially true or our default position?
Given out following Hypothesis test for the mean, how many tails are in the distribution: Ha=800 Ho/= 800
Increase sample size
If we wanted to make the confidence interval narrower without changing the level of confidence, we would need to do what?
Simple random sample
Probability distribution for all possible sample means is known as a
As the sample size _____ ; the standard error ____
Central Limit Theorem
Theorem that allows us to use the normal probability distribution to approximate the sampling distribution of sample means and sample proportions whenever the sample size is large, (n>30) is known as what?
absolute value of the difference between the sample mean and the sample deviation
Type of sample where every tenth person is selected after the first selecting someone at random is?
In hypothesis testing if the null hypothesis has been rejected when the alternative hypothesis is ____
what is correct notation for the critical values of a two tailed test
Tells how many standard errors we can go from hypothesized value
Reduced sampling error
advantage of using matched sample instead of independent random samples
ratio of the two sample variances
tells us how many standard errors apart the sample means are
distribution is discrete, has two outcomes and has known probabilities of succes
distribution is discrete, has two outcomes and is time sensative
Extreme observation that is a very large or very small relative to the data?
Hypothesis testing for the mean
There are 3 sets of alternative and null hypothesis
Two Sample T-test
What is best used in comparative studies
in testing variance homogeneity we use,
Left has a lower mean
Diagram of two curves: The left in higher than the right
F-Test for variance equality
I have a SRS to gsu students. 1 sample has an avg. of 45, deviation of 10, and sample size of 250. What do you have to do first in order to test for statistical mean difference?
as we increase the allowed degrees of freedom in a T-distribution, it becomes closer to what?
the probibility of our test statistic (tcalc) is represented by?
the probability of our critical value (tcrit) is represented by?
From the example, what is the area under the curve from 2.14 to infinity?
indicative of a linear relationship
standard deviation squared
show that sample represents the population
percentage went down (per unit)
Steps in taking a sample
1. define purpose 2. identify population 3. determine sampling method 4.Develop/Analyze Survey 5. Analyze Data
measurements of range, spread, or variance of variation
when the given events encompass all the sample space
limited within their range
unlimited within their range
only 2 outcomes; Each trial is independent and identical
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