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Stats 6.2-7.4
Test 3
| Question | Answer |
|---|---|
| 6.2 | |
| uniform distribution | values spread evenly over the range of possibilities |
| Standard normal distribution | normal probability distribution with mean=0 and stand. deviation=1 |
| normal cdf | probability |
| inv.norm. | z-score |
| 6.3 | |
| z score formula | x-mean/stand. dev. |
| Standard error of the mean o x | mean/square root of n |
| Sample of Values | _ x-mean/stand.Dev./Sqare root of n |
| 7.2 | |
| Point Estimate | single value(or point) used to approximate a population parameter |
| Confidence Interval | range of values used to estimate the true value of a population parameter |
| Confidence level | probability 1-a |
| critical value | number on the borderline seperating sample statistics that are likely to occur from those that are unlikely to occur(z a/2) |
| Margin of error | denoted by E,maximum likely difference |
| Round off rule-CI | 3 digits |
| Round off rule-Sample size | larger whole number, can't have half a person |
| sample size for population mean | n=[za/2o /e]^2 |
| Degrees of Freedom | number of sample values that can vary after certain restrictionsw have been imposed on all data values |
| Degrees of freedom formula | n-1 |
| Zinter | mean is known and n>30 |
| Tinter | mean NOT known and n>30 |