Data Analysis: exam 2

T/F; when we engage in statistical significance testing we go from a sample distribution to a population. And one should be a close approximation to another.

T/F; when we engage in statistical significance testing, the key statistical that allows us to move from the sample to the population is the standard error of the mean and the standard error of sample standard deviation

when we engage in statistical significance testing, we typically use 3 basic statistics to compute the standard errors. which ones are these? (check all that apply)

1. Mean

2. Standard Deviation

3. N (or size of sample)

T/F; the perfect sampling distribution should have relatively the same mean as that of the population.

T/F; our sample and population distributions are not going to match perfectly.

T/F; we can use our knowledge of sampling distributions to determine the correct number of shoes (and size) of each one to assemble and distribute across the world.

T/F; probably, the best approximation of the mean in a population is the calculate a mean of means. That is, if you took a representative sample, and then sampled 1,000+ times and plotted the mean, the average of this new distribution should very close to the population mean.

T/F; a smaller std. error generally means that the statistics you compute is less variable and likely closer to the population mean.

we compute standard error for almost every inferential statistic we will cover in this class

T/F; the standard error is a measure of variation

T/F; theoretical (or sampling) distributions will always plot normal.

T/F'; the standard error generally has a denominator that takes the square root of some variant of N.

T/F; T-est and regressions are related mathematically but conceptually test two different things.

T/F; the sum of squares formula is a mathematical shortcut that allows us to compute complex mathematics easily and more efficiently.

T-test make use of 3 basic descriptive statistics in their formula. What statistics are used in its computations?

1. Mean

2. SD

3. N

T/F; if we measure people’s attitudes towards a concept like the death penalty both before and after they see a video of an actual execution, we can use a t-test to determine if the intervention (video) affected their perception.

T/F; the denominator in the formula for a t-test is usually a standard error. We use the standard error to got through a wormhole and compare our results to go theoretical distribution.

T/F; a one tailed test always states a direction or claims that one distribution or sample has more (or less) than another.

T/F; a two tailed test does not state a direction and only claims that two distributions are different.

T/F; when we run t-test on our calculator , we always take the kids to the pool.

T/F; ANOVA analysis is conceptually similar t-test, but it typically involves comparing three or more populations.

T/F; I can run both t-test and a one-way ANOVA on my calculator

T/F; when completing a t-test, the value of T tells you if your results are statically significant or not.

T/F; when completing a t-test, the value of P (or sometimes called Sig Value) tells you how many times you are going to make a type 1 error ( and indirectly a type 2 error through the size of the sample)

the hypothesis that states hybrid dogs (e.g. poodles and old English sheepdog mix) live longer then pure bred dogs, is a ___ tail.

T/F; it is helpful to state and understand the mathematical hypothesis because it reminds the researcher exactly what the test is doing.

the mathematical null hypothesis for regression is that the regression variate (or slope) is equal to ___

a man who receives notice from his doctor’s office that he is pregnant when he is not, is an example of what type of statistical error?

T/F; the hypothesis that states that hybrid dogs (e.g. poodles and old English sheepdog mix) live longer then pure bred dogs, is a ___ tail test.

T/F; the dependent variable is typically referred to as Y

T/F; for a one-tailed test, the critical region is focused on one end of the theoretical distribution

T/F; for a two-tailed test, the critical region is focused on both ends of the theoretical distribution

T/F; the independent variable is typically referred as X

T/F'; researchers working with very large data sets often set their alpha levels very high because the more cases you have, the more likely you are to produce significant.

T/F; the denominator of the formula for a t-test is referred as the standard error of the difference.

T/F; the mathematical null hypothesis for a two-sample independent t-test is that mean for the first group is equal to the mean for the second group.

a sample t-test uses what three statistical to compute its value? the mean, the standard deviation, and ___?

the degrees of freedom for a one-sample t-test is equal to ____?

T/F; a t-est that uses one distribution and compares its values to a stated or population mean is referred to as a ____ t-test?

with large samples (N > 100) if we produce a t-value of 1.25, we are fairly sure the differences between are going to be significant/

T/F; the formula for a t-test in its simplest form takes the difference between two samples and compares its values to what it would expect to take and compares that value to a theoretical distribution.

T/F; with large samples (N > 100) if we produce a t-value of 1.96 or greater, we are fairly sure that the difference between samples is going to be significant.