Stats 1430 Final Exam

Stats 1430 Final Exam p-value characteristics (for HT population mean) - ✔✔depends on data, changes with each sample, sig level alpha stays the same once its is chosen can outliers affect the CI - ✔✔yes if x is not n ...

Stats 1430 Final Exam p-value characteristics (for HT population mean) - ✔✔depends on data, changes with each sample, sig level alpha stays the same once its is chosen can outliers affect the CI - ✔✔yes if x is not normal for CI, what must be known - ✔✔population standard deviation parameter - ✔✔what you are looking for (number describes pop) sampling dist - ✔✔set of all values of a stat for all possible samples of size n from the population the mean of all the sample means equals - ✔✔mean of the population (mu xbar= mux) as population standard deviation increases, standard error... - ✔✔increases if random variable X has a normal distilled, then x bar has a _________ shape - ✔✔normal the mean of x bar equals the mean of ____ - ✔✔X (all the time) as n increases, standard error..... - ✔✔decreases the standard error of x bar is ______ than standard deviation of X - ✔✔less if X has normal distilled, x bar has... - ✔✔exact normal diet for any n 3 items affect the margin of error of a CI: - ✔✔z-value, n, standard deviation of the population as confidence level of CI increases, the z-value... - ✔✔increases The object of a HT is to challenge a claimed value of a - ✔✔population parameter alternative hypothesis - ✔✔the one we believe is correct, Ha test statistic - ✔✔When doing a HT: collect data, find stat, change it to a z-score (name given to z-score) p-value - ✔✔the probability of being at or beyond your z-score in the direction of your alternative hypothesis (HT def) if you have enough evidence against Ho and are able to reject it, the p-value must have been - ✔✔small (less than .05) the closer your test stat is to the middle of the z-dist, the ________ likely you are to reject Ho - ✔✔less conditions for binomial dist - ✔✔np >=10, n(1-p)>=10 if X has an unknown dist, x bar has an approximately ________ dist if sample size is large enough - ✔✔normal we use stats to estimate: - ✔✔population parameters as n increases, the mean of x bar... - ✔✔stays the same as standard error increases, the sample size of x bar... - ✔✔decreases increasing the CI and population standard deviation ( increases or decreases) the MOE - ✔✔increases what does CLT apply to - ✔✔shape There is a _____ chance that your sample mean lies within your 95% CI - ✔✔100% if X has a normal dist, then the sampling distilled of x bar is __________ - ✔✔exactly normal for any n can p-values change if you take a new sample - ✔✔yes large p-values mean you have ______ evidence against Ho - ✔✔little p hat is the _______ proportion - ✔✔sample why does the formula for a CI for p involve a z value - ✔✔because of the central limit theorem a p value in HT testing means the same thing as the sample proportion (T/F) - ✔✔false if you have a z value of .6, that means 60% of the data lie below you (T/F) - ✔✔false a normal probability plot showing a straight line indicates what type of dist? - ✔✔normal as n increases, what happens to mu x bar? - ✔✔stays the same P(z<-2.72)= P(z>2.74) (T/F) - ✔✔true if you want to estimate the pop mean, which technique do you use - ✔✔find a CI for u if X is a random variable with a standard deviation of 10, then 3X has a standard deviation of - ✔✔30 the variance of X+Y= the variance of X + the variance of Y if X and Y are independent (T/F) - ✔✔true when to use binomial distribution - ✔✔counting yes/ nos in a series of n trials or sample size of n, only 2 categories population - ✔✔entire group of interest sample - ✔✔subject of entire group what 3 things must be found out about the sampling distribution to make inferences about population parameter - ✔✔mean, spread (standard deviation) and shape Confidence Interval - ✔✔a range of likely values for the parameter factors that affect moe - ✔✔confidence level (direct), n (inverse) , population standard deviation (direct) can you have a high level of confidence yet a small Moe? - ✔✔yes, use a large n when looking at CI for population mean formulas must be... - ✔✔normal or use large n significance level - ✔✔pre-set cutoff (.05) p hat - ✔✔proportion of yeses in a sample, sample statistic conditions for CI for pop proportions - ✔✔nphat>=10, n(1-phat)>=10 quick way to estimate MOE - ✔✔1/ square root of n hypothesis tests give information about.. - ✔✔population parameters (p), not sample stays like phat if the sample mean increases, what happens to MOE - ✔✔nothing, stays the same in a two-tailed hypothesis, any values within the confidence interval will result in the decision to __________ the null hypothesis - ✔✔fail to reject random variable - ✔✔characteristics that takes on random values, values unknown until data is collected discrete random variable - ✔✔finite, can be measured continuous random variable - ✔✔cannot be measured if X is a continuous random variable. then P(X=x)= - ✔✔0 for any value of X examples of discrete random variables - ✔✔number of accidents on a busy highway, number of red cares that go by out of a sample of 100 NOT EXAMPLE: time between accidents on a busy highway we find a probability for a continuous random variable X by finding the _________ under the ________ - ✔✔area under the curve normal distribution is/ shape - ✔✔continuous and symmetric if X is above the mean, the Z score will be a ______ number - ✔✔positive a z-value tells you how many _______ the X value is above or below its ______ - ✔✔standard deviations, mean the z-table always gives you the probability of being _____ than the number you are looking up - ✔✔less