Quantitative Methods Study Guide Exam, Exams of Research Methodology

Download Quantitative Methods Study Guide Exam and more Exams Research Methodology in PDF only on Docsity! QUANTITATIVE METHODS STUDY GUIDE EXAM QUESTIONS WITH ANSWERS, GUARANTEED PASS, PROFESSOR VERIFIED, RATED A+ t test - ANSWER Hypothesis-testing procedure in which the population variance is unknown; it compares t scores from a sample to a comparison distribution called a t distribution. t test for a single sample - ANSWER hypothesis-testing procedure in which a sample mean is being compared to a known population mean and the population variance is known. biased estimate - ANSWER Estimate of a population parameter that is likely systematically to overestimate or underestimate the true value of the population parameter. For ex. SD² would be a biased estimate of the population variance [it would systematically underestimate it]. t test - ANSWER Is sometimes called "Student's t" because its main principles were originally developed by William S. Gosset, who published his research articles anonymously using the name "Student". Scores - ANSWER If the _________in the population have a lot of variation, then the __________in a sample randomly selected from the population should also have a lot of variation. Little - ANSWER If the population has very _________variation, the scores in a sample from that population should also have very _________variation. Variance - ANSWER You could figure the __________of the sample's score, and that should be similar to the ______ of the scores in the population. Variance - ANSWER The ___________of a sample will generally be slightly smaller than the ___________ of the population from which it is taken. Unbiased estimate of the population variance [S²] - ANSWER Estimate of the population variance, based on sample scores, which has been corrected so that it is equally likely to overestimate or underestimate the true population variance: the correction used is dividing the sum of squared deviations by the sample size minus, 1, instead of the usual procedure of dividing by the sample size directly. Degree of freedom [df] - ANSWER Number of scores free to vary when estimating a population parameter; usually part of a formula for making that estimate--for example, in the formula for estimating the population variance from a single sample. t distribution - ANSWER Mathematically defined curve that is the comparison distribution used in a t test. t table - ANSWER Table of cutoff scores on the t distribution for various degrees of freedom, signifiance levels, and one-and two-tailed tests. t score - ANSWER Is your sample's mean minus the population mean, divided by the standard deviation of the distribution of means. Variance of a distribution of means - ANSWER To find the ____________, you always divide the population variance by the sample size. Population variance - ANSWER It is only when making the estimate for the ___________ that you divide by the sample size minus 1. Repeated measure design - ANSWER Research strategy in which each person is tested more than once; same as within-subjects design. Difference scores - ANSWER Difference between a person's score on one testing and the same person's score on another testing; often an after-score minus a before score, in which case it is also called a change score. Null hypothesis - ANSWER Population 2 is the population for when the _________is true. alpha α - ANSWER Probability of making a type I error, same as significance level. Type II error - ANSWER Failing to reject the null hypothesis when in fact it is false; failing to get a statistically significant result when in fact the research hypothesis is true. Type I error - ANSWER Rejecting the null hypothesis when in fact it is true; getting a statistically significant result when in fact the research hypothesis is not true. beta ß - ANSWER Probability of making a type II error. Statistical power - ANSWER Probability that the study will give a significant result if the research hypothesis is true. t distribution - ANSWER Generally___________look to the eye like a normal curve--bell-shaped, symmetrical, and unimodal. t distribuation - ANSWER Differs subtly in having heavier tails [that is, slightly more scores at the extremes]. one-tailed test - ANSWER If you have a _____________, you need to decide whether your cutoff score is a positive t score of a negative t score. positive - ANSWER If your one-tailed test is testing whether the mean of Population 1 is greater than the mean of Population 2, the cutoff t score is _________. negative - ANSWER If your one-tailed test is testing whether the mean of Population 1 is less than the mean of Population 2, the cutoff t score is _________. Variance of a distribution of means - ANSWER To find the ____________________, you always divide the population variance by the sample size. This is true whether the population's ___________ is known or only estimated. Population 2 - ANSWER Is the population for when the null hypothesis is true. one-tailed test - ANSWER When doing a __________ if the sample of difference scores is highly skewed, suggesting the population it comes from is also highly skewed. one-tailed test - ANSWER The only very common situation in which using a t test for dependent means is likely to give a seriously distorted result is when you are using a _______ and the population is highly skewed [is very asymmetrical, with a much longer tail on one side than the other]. variance of a distribution of means - ANSWER To find the _____________, you always divide the population variance by the sample size. Step 3 of hypothesis testing - ANSWER Is determining the cutoff for rejecting the null hypothesis. positive - ANSWER If your one-tailed test is testing whether the mean of Population 1 is greater than the mean of Population 2, the cutoff t score is _________. negative - ANSWER If your one-tailed test is testing whether the mean of Population 1 is less than the mean of Population 2, the cutoff t score is __________. Step 4 of hypothesis testiing - ANSWER Is figuring your sample mean's score on the comparison distribution. Basically, find the t score. t=M-µ/SM Step 5 of hypothesis testing - ANSWER Is deciding whether to reject the null hypothesis.