2424685
Description
Flashcards by Amrit Bhogal, updated more than 1 year ago
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Created by Amrit Bhogal
about 9 years ago
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| Question | Answer |
| What two approaches are their to testing the uncertainty around the true slope? | 1. calculate a confidence interval around the slope 2. test the statistical signifcance of the slope by calculating a t ratio |
| TRUE/FALSE A confidence interval around the slope gives a range of values with a given probability of including the true slope. | True |
| What does a 95% confidence interval say about the true slope? | There is a 95 percent probability that the true slope will fall within the confdence interval |
| What is the amount of uncertainty estimated by? | The standard error of the slope |
| True/false The null hypothesis is the proposition that the true slope is one. | False, ...that the true slope is ZERO |
| What does a slope of zero imply? (2) | (1) the independent variable has no efect on the dependent variable, and (2) the slopecalculated in a sample is a result of nothing more than chance |
| What would support the null hypothesis? | If the slope is judged to occur frequently by chance |
| What is a research hypothesis? | A hypothesis that purports a relationship between the independent and dependent variable |
| What criterion constitutes "infrequently by chance"? What is it referred to as? | It should occur no more than 5% of the time by chance (referred to as alpha) |
| When is a slope said to be statistically significant? | when its frequency of occurring by chance is less than, or equal to, alpha |
| Which alpha percentage gives more leniency to a statistically significant number: 10% or 1% | 10% - to be considered statistically significant the slope should occur no more than 10% of the time by chance |
| In reference to the comparison between t(calc) and t(table), when is a slope significant | When t(calc) is greater than, or equal to the t (table) |
| A correct positive | when the slope is found to be statistically significant and the true slope is not zero |
| Power | The probability of a correct positive decision |
| Correct negative | When the slope is not statistically significant and the true slope is zero |
| false positive | slope is found to be statistically significant but the true slope is zero |
| A false positive is often called a Type One Error, what is the probability of making a type one error equal to? | It is equal to alpha |
| false negative | slope is not statistically significant but the true slope is not zero |
| a false negative decision is called a Type Two Error, what is it equal to? | 1 minus power (remember: power refers to the probability of getting a correct positive) - termed beta |
| True/false the steeper the slope, the weaker the effect of the independent variable | false |
| True/false the effect of an independent variable is not a function of sample size | true |
| Other things equal, how does a larger sample size affect the t-ratio and probabiliy | As the sample size increases: - t ratio gets larger - probability gets smalled |
| Give an example showing that the effect of an independent variable is not a function of sample size | Scotch on the Central nervous system |
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