STAT 201 EXAM 3 QUESTIONS ANSWERED CORRECTLY LATEST UPDATE 2026

STAT 201 EXAM 3 QUESTIONS ANSWERED CORRECTLY LATEST UPDATE 2026 The conditions for a sampling distribution of a sample mean, when you know the true mean, are... - AnswersRandomization, 10% Condition, Large Enough Condition The sampling distribution of the sample mean will always have the same _____ as the original distribution - AnswersMean When the population mean and standard deviation are known, what distribution is used for the analysis of the sample? - AnswersNormal Distribution No matter what the shape of the parent population is, as long as our sample size is 10 or greater, we can conclude that the sampling distribution of the sample mean is approximately normally distributed. - AnswersTrue Which of the following is not a requirement for a testing means? Randomization, Success/Failure Condition, 10% Condition, Nearly Normal Condition - AnswersSuccess/Failure Condition A new diet is being tested. The inventor claims people lose 10 pounds on average after 6 weeks. 25 people are randomly picked to try the diet. Researchers are concerned the inventor's claim is exaggerated. The sample yields an average of 1.9 and a standard deviation of 6. Calculate the appropriate test statistic. Enter with 2 decimals (eg. 1.96). - Answers-6.75 A new diet is being tested. The inventor claims people lose 10 pounds on average after 6 weeks. 25 people are randomly picked to try the diet. Researchers are concerned the inventor's claim is exaggerated. Which is the correct set of hypothesis statements? Ho: mu = 10 lbs vs. Ha: mu 10 lbs Ho: mu 10 lbs vs. Ha: mu 10 lbs Ho: mu 10 lbs vs. Ha: mu 10 lbs - AnswersHo: mu = 10 lbs vs. Ha: mu 10 lbs If we construct a 95% confidence interval that does not contain the hypothesized value, which of the following statements is true? We can reject that value at 0.05 alpha We can not reject that value at 0.05 alpha - AnswersWe can reject that value at 0.05 alpha True or False: A smaller p-value provides stronger evidence against the null hypothesis. - AnswersTrue True or False: Lower P-values are evidence of a cause and effect relationship - Answersfalse A new diet is being tested. The inventor claims people lose 10 pounds on average after 6 weeks. 25 people are randomly picked to try the diet. Researchers are concerned the inventor's claim is exaggerated. The sample yields an average of 7.5 and a standard deviation of 6.5. Calculate the appropriate test statistic. Enter with 2 decimals (eg. 1.96). - Answers-1.92 A Type II error is when: - AnswersThe null hypothesis is false and we fail to reject When we reject the null and the null is true, what type of error is that? - AnswersType 1 The results of a Chi-square test for independence concludes color choice is dependent on the gender of the Kindergartner. What does this tell us about the p-value in relation to the alpha level? - AnswersThe p-value was lower than the alpha level the overall Chi-square test statistic is found by ___ all the cell Chi-square values - Answersadding True or False: Chi-Square tests are used for testing hypothesis of the association between two categorical values - AnswersTrue True or False: The sample size of each group must be the same for a two-sample t-interval - AnswersFalse Central Limit Theorem (CLT) - Answersthe sampling distribution derived from a simple random sample will be approximately normally distributed Condition for Central Limit Theorem (CLT) - AnswersRandomization Condition, 10% Condition, and Large Enough Sample Condition 10% Condition - Answerssample size, n, should be no larger than 10% of the population Randomization Condition - Answersthe data values must be sampled randomly Large Enough Sample Condition - AnswersIf the population is unimodal and symmetric, even a fairly small sample is okay. For highly skewed distributions, it may require samples of several hundred for the sampling distribution of means to be approximately Normal. What is the Normal model? - AnswersA close approximation of the sampling distribution of the sample mean for the smaller sample size when the population is close to a Normal distribution itself What is a degree of freedom? - Answersfamily of related distributions that depend on a parameter True or False: T-models with only a few degrees of freedom have a much fatter tail than the Normal Distribution. - AnswersTrue True or False: Confidence intervals for t-model's are smaller than if the Normal model was applied - AnswersFalse, they are wider What are the assumptions and conditions for T-tables? - AnswersIndependence assumption, Randomization Condition, 10% Condition, Normal Population Assumption, Nearly Normal Condition (Unimodal and Symmetric) Independence Assumption - Answersall data values should be independent Normal Population Assumption - Answersassume the errors around the idealized regression line at each value of x follow a normal model Nearly Normal Condition - AnswersA distribution is nearly Normal if it is unimodal and symmetric. We can check by looking at a histogram or a Normal probability plot. True or False: The larger the sample size, the closer the data should follow a Normal Model - AnswersFalse, the smaller the sample size, the closer the data will be to the Nearly Normal model True or False: Sample sizes larger than 40 or 50, t-methods are safe to use - Answerstrue What is the initial hypothesis called? - AnswersNull Hypothesis what is H(little a) - AnswersAlternative Hypothesis What is the Null hypothesis a statement of? - Answersthe value of the population parameter What are the 3 possible alternative hypothesizes? - AnswersHA: parameter ≠ hypothesized value HA: parameter hypothesized value HA: parameter hypothesized value What is the probability of getting the sample data that we collect called, if the null hypothesis is true? - AnswersP-value P-value over .05 means... - Answers"we fail to reject the null hypothesis" P-value smaller than .05 means... - Answers"we reject the null hypothesis" True or False: HA: parameter ≠ value is a one-side alternative - AnswersFalse, it is two-sided because we are equally interested in deviations on either side of the null hypothesized vlaue What is a one-sided alternative? - AnswersAn alternative hypothesis focused on deviations from the null value in only one direction How can you approximate a hypothesis test? - Answersby examining the confidence interval What does the term "threshold" refer to? - AnswersLevel of Significance or alpha value (little a) What do large P-values mean? - Answerswhat we are observing isn't surprising. True or False: If our P-value falls below our threshold, we'll reject the null hypothesis. Can we can call these results statistical significant? - AnswersYes What are the common alpha levels? - Answers0.10, 0.05, 0.01 What is the Effect Size? - AnswersThe difference between the hypothesized value of the parameter and the actual value of the parameter What is a type I error? - AnswersWhen the null is true, and we reject it What is a type II error? - AnswersWhen the null is false, and we fail to reject it what does beta represent? - AnswersThe probability of committing an type II True or False: The larger the effect size, the larger beta will be - AnswersFalse; The larger the effect size, the smaller beta will be True or False: the larger the alpha level, the smaller beta is - Answerstrue True or False: The larger the sample size, the larger beta will be - AnswersFalse; the larger the sample size, the smaller beta will be What is the power of a test? - Answersthe probability that it correctly rejects a false null hypothesis (1-beta) What does power depend on? - Answerssample size and alpha level What is the parameter of interest? - Answersthe difference between the two population means True or False: Sampling distribution of the difference in sample means of two independent groups of a Student's t - Answerstrue What is the confidence interval called when finding the difference in means? - Answerstwo-sample t-interval What is a two-sample t-test? - Answersthe corresponding hypothesis test for a two-sample t-interval What are the assumptions and conditions when comparing two means with t-tests/t-intervals? - AnswersNormal Population Assumption: Nearly Normal Condition Independent Group Assumptions: Independent groups What does a contingency table do? - Answerscategorizes counts on two categorical variables so that we can see wether the distribution of counts on one variable is contingent on the other What is a test of independence? - Answersexamine whether there is a significant association between a pair of categorical variables Assumptions and Conditions for Tests of Independence - AnswersCounted Data Condition,