Term
| What are the two branches of statistics? |
|
Definition
| descriptive and inferential |
|
|
Term
| One of the most common uses of the inferential branch is to use sample statistics, such as ___, to estimate population parameters, such as ___. |
|
Definition
|
|
Term
| X bar is a ____of mu because x should be pretty close to the value of mu. |
|
Definition
|
|
Term
| What do sample statistics estimate? |
|
Definition
|
|
Term
| If x bar is a point estimate of mu than p hat is a point estimate of ___. |
|
Definition
|
|
Term
| We know the value of x bar is porbably pretty close to mu, but we want to get even closer. So rather than just say x bar is close to mu, we are going to build an interval around x bar, and then say that mu probably lies somewhere on this interval. We call this an____. |
|
Definition
|
|
Term
| Since we can't get the full population mean, we go for the next best thing. WE take a sample and calculate a sample mean and what we add and subtract from the sample mean to get the interval estimate is the _____. |
|
Definition
|
|
Term
| When we construct interval estimates, we call them_____. |
|
Definition
|
|
Term
| So a confidence interval of a parameter consists of an interval of numbers, and this interval is our_____. |
|
Definition
| point estimate +/-our margin of error |
|
|
Term
| WE call the value we obtain when we take the point estimate MINUS the margin of error the_____or______. |
|
Definition
| lower limit or lower bound |
|
|
Term
| We call the value we obtain when we take the point estimate plus the margin of error the_____or_____. |
|
Definition
| upper limit or upper bound |
|
|
Term
| As you increase the level of confidence, what happens to the size of the interval? |
|
Definition
|
|
Term
| How do you calculate the wdith of a confidence interval? |
|
Definition
| subtract the upper limit from the lower limit |
|
|
Term
| How do you calculate the sample mean if you know the confidence interval? |
|
Definition
| add the lower limit and the upper limit and divide by two |
|
|
Term
| The sample mean, x bar will always be in the middle of the confidence interval. The sample mean x bar will always be in the confidence interval but the population mean ___may or may not be on the confidence interval. |
|
Definition
|
|
Term
| How do you calculate the margin of error if you know the sample mean and the confidence interval? |
|
Definition
| subtract the sample mean from the upper limit. or subtact the lower limit from the sample mean |
|
|
Term
| The level of confidence is always written as a ____. |
|
Definition
|
|
Term
| When dealing with population proportions, the confidence interval is the sample proportion p hat. P hat can be determined by dividing x/n. X is ________and n is _____. |
|
Definition
| x is the number of indviduals in the sample with the desired characteristic and n is the sample size |
|
|
Term
| The ____will always be a multiple of the standard error. |
|
Definition
|
|
Term
| The standard error when constructing a confidence interval to estimate a population proportion will be: |
|
Definition
|
|
Term
| The margin fo error when constructing a confidence interval to estimate a population proportion will always be _____. |
|
Definition
| some number times the formula to calculate standard error for a population proportion. The number you multiply by the standard error to get the margin of error completely depends on the level of confidence |
|
|
Term
| What is the general formual for a confidence interval for a population proportion? |
|
Definition
| p hat +/- Z sqrt p hat(1- phat)/n |
|
|
Term
| In 95 percent confidence intervals, the Z value equals ____. |
|
Definition
|
|
Term
| For these confidence intervals to be valid, we need to check some requirements as we did back when we were determinng the sampling dsitribution for the sample proportion. The following two things must be true: |
|
Definition
n(p hat) greater than or equal to 15 AND
n(1-p hat) greater than or equal to 15 |
|
|
Term
| The drug Lipitor is meant to lower cholesterol levels. In a clinical trial of 884 randomly selected patients who received 10 mg doses of Lipitor daily, 221 reported a headache as a side effect. Obtain a point estimate for the population proportion of users who will experience a headache. |
|
Definition
|
|
Term
| The drug Lipitor is meant to lower cholesterol levels. In a clinical trial of 884 randomly selected patients who received 10 mg doses of Lipitor daily, 221 reported a headache as a side effect. Verify that the requirements for constructing a confidence interval about p are satisfied. |
|
Definition
n(p hat)=221 which is greater than 15
n(1- p hat)=663 which is greater than 15
yes it is a valid interval |
|
|
Term
| How do you find 1.96 for a 95% confidence interval? |
|
Definition
| 1-.95=.5 .5/2=.025. put it stat crunch calculator with mean=zero and sd=1, hit compute and you get 1.96 |
|
|
Term
| How do you find the z score for a 90% confidence interval? |
|
Definition
| 10/100/2=.05 go to stat, calc, normal, plug in a mean of zero and a sd of 1. look for the second blank and plug .05 in the third blank. the second blank will be the z score |
|
|
Term
| To get the margin of error you multiply the ____by the standard error. |
|
Definition
|
|
Term
| Can there ever be a 100 percent confidence interval? |
|
Definition
|
|
Term
| What happens to the interval if you increase the sample size? |
|
Definition
|
|
Term
| As the level of confidence increases, the margin of error____and the confidence interval gets______. |
|
Definition
|
|
Term
| AS the level of confidence decreases, the margin of error_____and the confidence interval gets_____. |
|
Definition
|
|
Term
| As the sample size increases, the margin of error_____and the confidence interval gets_____. |
|
Definition
|
|
Term
| As the sample size decreases, the margin of error_____and the confidence interval gets_____. |
|
Definition
|
|
Term
| When calculating the confidence interval for the population proportion, the symbol for point estimate is what? |
|
Definition
|
|
Term
| When calculating the confidence interval for the population proportion, what is the formula for margin of error? |
|
Definition
| Z[sqrt p hat(1- p hat)/n] |
|
|
Term
| When calculating the confidence interval for the population proportion, how do you find the standard error? |
|
Definition
|
|
Term
| How do you calculate the confidence interval for the population proportion? |
|
Definition
| p hat +/- sqrt phat(1-phat)/n |
|
|
Term
| Can you use statcrunch to calculate confidence intervals for population proportions? |
|
Definition
|
|
Term
| When you are constructing a confidence interval to estimate a population mean, what is the point estimate? |
|
Definition
|
|
Term
| When constructing a confidence interval to estimate a population mean, how do you find the standard error? |
|
Definition
|
|
Term
| What is s in the standard error formula when constructing a confidence interval to estimate a population mean? |
|
Definition
|
|
Term
| How do you find degrees of freedom? |
|
Definition
|
|
Term
| How do you calculate the confidence interval for a population mean? |
|
Definition
|
|
Term
| When is the confidence interval for a population mean considered valid? |
|
Definition
| when you use a random sample AND either use a sample size >30 OR when we are sampling from a normal population |
|
|
Term
| When you are constructing a confidence interval for a population mean, what is the point estimate? |
|
Definition
|
|
Term
| When you are constructing a confidence interval for a population mean, how do you find the margin of error? |
|
Definition
|
|
Term
| HOw do yuo find the standard error when you are constructing a confidence interval for a population mean? |
|
Definition
|
|
Term
| HOw dyou find a confidence interval for a population mean? |
|
Definition
|
|
Term
| When the null hypothesis is rejected, we say that there is or is not enough evidence to reject the null hypothesis and side with the alternative hypothesis? |
|
Definition
|
|
Term
| When the null hypothesis is not rejected, do we say there is or is not enough evidence to reject the null hypothesis? |
|
Definition
|
|
Term
| When performing significance tests about a population proportion, what three assumptions must be true? |
|
Definition
| the data is categorical, the data are obtained using randomization, we need the shape of the sampling distribution of the sample proportion to be approximately normal (np >15 and n(1-pnought)>15 |
|
|
Term
| What is the p value if it is a right tailed test? |
|
Definition
| the area to the right of the z score |
|
|
Term
| What is the p value if you are doing a left tailed test? |
|
Definition
| the area to the left of the z score |
|
|
Term
| What is the p value if you are doing a two tailed test? |
|
Definition
| the sum of the area to the left of the negatie z score plus the area to the right of the positive z score |
|
|
Term
| What is another word for significance value? |
|
Definition
|
|
Term
| What do you do if the p value is less than alpha? |
|
Definition
| reject the null hypothesis |
|
|
Term
| What do you do if the p value is greater than alpha(signifance value)? |
|
Definition
| we do not reject the null hypothesis |
|
|
Term
| When performing significance tests about a population mean, what three assumptions need to be true? |
|
Definition
| the variable is quantitative, the data are obtained using randomization, the population distribution is approximately normal or we are using a sample size greater than 30 |
|
|
Term
| What is a type one error? |
|
Definition
| we reject H nought when H in fact H nought is true |
|
|
Term
|
Definition
| We do not reject H nought when in fact H nought is false and Ha is true |
|
|
Term
| If a type 1 error was made, what three statements would apply? |
|
Definition
| the null hypothesis was rejected, the researcher decided there was enough evidence to indicate a change in the mean age, actually the mean age has not changed significantly |
|
|
Term
| If a type two error was amde, which of the following statements would apply? |
|
Definition
| the null hypothesis was not rejected, the researcher decided there was not enough evidence to indicate a change in the mean age, actually the mean age has changed significantly |
|
|
Term
| A type one error means we reject the null hypothesis when the null hypothesis is_____. |
|
Definition
|
|
Term
| A type two error means we do not reject the null hypothesis when the null hypothesis is _____. |
|
Definition
|
|
Term
| If the confidence interval contains the value we are testing then do we reject or not reject the null hypothesis? |
|
Definition
| we do not reject the null hypothesis |
|
|
Term
| IF the confidence interval does not contain the value we are testing then do we reject or not reject the null hpothesis? |
|
Definition
|
|
Term
| Are you more likely to reject H nought with a large or small p value? |
|
Definition
|
|
