STA 271 Final Exam Questions and Answers 100% Pass

STA 271 Final Exam Questions and Answers 100% Pass one sample z test - ANSWER-1 - State null/alternate hypotheses [ex] test the hypothesis that the mean weight gain of pregnant women was more than 30 pounds... null hypothesis: H₀: μ = 30 alternate hypothesis: H₁: μ 30 _____________________________ 2 - use z-formula to find z-score [ex] 1,500 women followed the Atkin's diet for a month. A random sample of 29 women gained an average of 6.7 pounds. Test the hypothesis that the average weight gain per woman for the month was over 5 pounds. The standard deviation for all women in the group was 7.1. Z = 6.7 - 5 / (7.1/√29) = 1.289. Copyright © KAYLIN 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH NOVEMBER, 2024 Copyright ©Stuvia International BV Page 2/10 _____________________________ 3 - Look up z score in z-table [ex] The sample score above gives you an area of 0.8997. This area is your probability up to that point (i.e. the area to the left of your z-score). For this one sample z test, you want the area in the right tail, so subtract from 1: 1 - 0.8997 = 0.1003. z-formula - ANSWER-z = (sample mean minus hypothesized mean) divided by (standard deviation divided by square root of the number of sample items) test statistics (and be able to set up hypothesis, find p value, conclude) - ANSWER-Define: A test statistic is used in a hypothesis test when you are deciding to support or reject the null hypothesis. The test statistic takes your data from an experiment or survey and compares your results to the results you would expect from the null hypothesis. define p-value - ANSWER-an area in the tail of a distribution that tells you the odds of a result happening by chance. What are the four types of test statistics? - ANSWER-Z-SCORE, T-SCORE, F-STATISTIC, CHI-SQUARE STATISTIC When do you use the T-Score Formula? - ANSWER-When you don't know the population standard deviation and you have a small sample (under 30) Copyright © KAYLIN 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED FIRST PUBLISH NOVEMBER, 2024 Copyright ©Stuvia International BV Page 3/10 What is the T-Score Formula? - ANSWER-t = (sample mean minus population mean) / (sample standard deviation divided by √(sample size)) What do we look at when looking at T-score? - ANSWER-The larger the t score, the larger the difference is between the groups you are testing. It's influenced by many factors including: • How many items are in your sample. • The means of your sample. • The mean of the population from which your sample is drawn. • The standard deviation of your sample. degrees of freedom (df) - ANSWER-number of items in sample minus one (n-1) confidence interval - ANSWER-(not a percentage) a range of values; if you repeat experiment over and over, you have a confidence level of X% that your results would fall in the same range confidence level - ANSWER-(a percentage) the CL (X%) means that if you were to repeat an experiment over and over, then X% of the time, the results w