Biostatistics Homework Anova Models

Activity 7 6.2 The mean salary in the United States is a hypothetical average of $25,000. Determine if the mean salary of the participants in Practice Dataset 2 in Appendix B is significantly greater than this value. Note that this is a one-tailed hypothesis. The output returns a significance value of .069 for a two-tailed hypothesis. Knowing that this is a one- tailed hypothesis, divide that by 2. .069/2 = .0345 which is less than 0.05 so this is statistically significant. 6.3 Use Practice Dataset 1 in Appendix B to solve this problem. We believe that young individuals have lower mathematics skills than older individuals. WE would test this hypothesis by comparing participants 25 or younger (the “young” group) with participants 26 or older (the “old” group). The mean for the “young” group is 35.1818 and the mean for the “old” group is 31.4167. The significance value for the young group came back as .377 and the significance value for the old group came back as .374. Both of these values are more than .05 so this is not statistically significant. 6.4 Practice exercise: Use the same GRADES.sav data file, and compute a paired-samples t test to determine if scores increased from midterm to final. The mean scores for midterms was 78.6190 and the mean scores for finals was 86.1429. The significance value is <.001 which means that there is a significant increase in the scores. 8.3 Practice exercise: Using Practice Dataset 1 in Appendix B, determine if younger participants (<26) have significantly lower mathematics scores than older participants. The null hypothesis states that the skill level between the “young” group and the “old” group are the same. The significance value is returned as .525 which is greater than the significance value of .050. We retain the null hypothesis; there is no significant difference in the skill level between the two groups. 8.4 Practice example: This study source was downloaded by 100000788431644 from CourseHero.com on 10-11-2021 15:45:11 GMT -05:00 https://www.coursehero.com/file/79114404/Activity-7docx/ Th is stu dy re so ur ce w as sh are d v ia Co ur se He ro .co m https://www.coursehero.com/file/79114404/Activity-7docx/ Use the RACE.sav data file to determine whether or not the outcome of short-distance races is different from that of medium-distance races. Phrase your results. The null hypothesis states that there is no difference between short and medium distance races. The significance value returned was .438 which is greater than the significance level of .05, meaning that the results were not statistically significant and we retain the null hypothesis that there is no difference between short and medium distance race results. This study source was downloaded by 100000788431644 from CourseHero.com on 10-11-2021 15:45:11 GMT -05:00 https://www.coursehero.com/file/79114404/Activity-7docx/ Th is stu dy re so ur ce w as sh are d v ia Co ur se He ro .co m Powered by TCPDF (www.tcpdf.org) https://www.coursehero.com/file/79114404/Activity-7docx/ http://www.tcpdf.org Sheet1 points possibe points possibe Directions: There are 5 questions in this exercise. Put your answers in column D. Pay attention to the red triangles - they offer hints. The points possible for each answer are given in column A. Make sure you read and DO every last example listed in the "How" book - if you are not getting the same answers as the book, try again. If totally lost, email me and we'll set up a zoom. All data noted in "Appendix B" can be found in the Canvas course module "Data Sets: How to Use SPSS" 100% 2 2 name - present First: read/do the Single-Sample t Test Section in the "How" book. Q1: The mean salary in the United States is a hypothetical average of $25,000. Determine if the mean salary of the participants in Practice Dataset 2 in Appendix B is significantly greater than this value. Note that this is a one-tailed hypothesis. Pay attention to the hints in the red triangle blocks 1 1 HO 1 1 H1 2 2 what test are you running? 2 2 what is being compared 2 2 to what? 2 2 significant difference - found or not found 2 2 t(x) 2 2 =y 2 2 p - 2 2 sample mean of 2 2 sd 2 2 was / was not significally greater than what 2 2 Therefor we (fail to reject or reject) (null or alternative) Hypothesis First, Read/do the Independent-Samples t Test Section Q2: Use Practice Dataset 1 in Appendix B to solve this problem. We believe that young individuals have lower mathematics skills than older individuals. We would test this hypothesis by comparing participants 25 or younger (the “young” group) with participants 26 or older (the “old” group). Hint: You may need to create a new variable that represents each age group. See Chapter 2 for help. 1 1 HO 1 1 H1 2 2 What is your test 2 2 comparing what and 2 2 What 2 2 was significant difference found? 2 2 t(?) 2 2 =? 2 2 p value 2 2 conlcusion on difference 2 2 between whom based on age(> or <=) 2 2 M= 2 2 sd 2 2 between whom based on age(> or <=) 2 2 M= 2 2 sd 2 2 Therefor we (fail to reject or reject) (null or alternative) Hypothesis First, read/do the Paired-Samples t Test section in the "How" Book. Q3: Use the same GRADES.sav data file, and compute a paired-samples t test to determine if scores increased from midterm to final. 1 1 HO 1 1 H1 2 2 Test 2 2 compare what 2 2 to what 2 2 mean of midterm 0 2 2 sd= 2 2 what is copared 2 2 mand of final 2 2 sd= 2 2 A significant increase from what was /was not found 2 2 t(?)= 2 2 ?? 2 2 p= 2 2 Therefor we (fail to reject or reject) (null or alternative) Hypothesis First, read/do the Mann-Whitney U Test section in the "How" Book. Q4: Using Practice Dataset 1 in Appendix B, determine if younger participants (< 26) have significantly lower mathematics scores than older participants. (Note: You will need to create a new ordinal variable representing each age group. See Section 2.2 if you need a refresher on how to do that.) 1 1 H0: 25 and younger)math skills are not= 1 1 H1: 25 and younger)math skills are= 2 2 what test 2 2 different in what 2 2 of population 1 2 2 vs population 2 2 2 No what 2 2 U= 2 2 P= 2 2 Therefor we (fail to reject or reject) (null or alternative) Hypothesis First, read/do the Wilcoxon Test section in the "How" Book. Q5: Use the RACE.sav data file to determine whether or not the outcome of short-distance races is different from that of medium-distance races. Phrase your results. 1 1 h0 Elizabeth Tait: Elizabeth Tait: The null hypothesis is always the one that includes the equality The null hypothesis is always stated in the negative. This is because you have to be able to prove something is indeed true. Elizabeth Tait: Elizabeth Tait: The null hypothesis is always the one that includes the equality The null hypothesis is always stated in the negative. This is because you have to be able to prove something is indeed true. Elizabeth Tait: Elizabeth Tait: A null hypothesis is a hypothesis that says there is no statistical significance between the two variables. The null hypothesis is always the one that includes the equality. The null hypothesis is always stated in the negative Elizabeth Tait: Elizabeth Tait: The null hypothesis is always the one that includes the equality The null hypothesis is always stated in the negative. This is because you have to be able to prove something is indeed true. Elizabeth Tait: Elizabeth Tait: The null hypothesis is always the one that includes the equality The null hypothesis is always stated in the negative. This is because you have to be able to prove something is indeed true. Elizabeth Tait: Elizabeth Tait: NOTE!! To divide or not to divide: My research has that the One sample t-test – the p-value should not be divided by 2. If you have other proof (or examples), let me know. Here are some single sample t-tests examples: https://www.statisticssolutions.com/conduct-interpret-one-sample-t-test/ https://statistics.laerd.com/spss-tutorials/one-sample-t-test-using-spss-statistics.php 1 1 h1 2 2 what is compared 2 2 of what 2 2 medium what 2 2 was significant difference found? 2 2 (Z what 2 2 p= 2 2 ?? race results were /were not significantly different from 2 2 ?? race results. 2 2 Therefor we (fail to reject or reject) (null or alternative) Hypothesis 124 124 100% Sheet2 6.2 A single sample t-test that compared the mean salary of the sample to a value of $25,000 was conducted. A single sample t-test that 2 compared the mean salary of the sample to a 2 value of $25,000 was conducted. 2 2 6.3 An independent samples t-test was calculated comparing the mean score of participants who identified themselves as over 25 years old to the mean score of participants who identified themselves as 25 years old or less. An independent samples t-test was calculated 2 comparing the mean score of participants who identified themselves as over 25 years old 2 to the mean score of participants who identified themselves as 25 years old or less. 2 2 6.4 A paired samples t-test was calculated to compare the mean midterm score to the mean final exam score. A paired samples t-test was calculated to 2 compare the mean midterm score 2 to the mean final exam score. 2 2 8.3 The Mann-Whitney U test was used to examine the difference in the mathematical skill level of older that 25 to those 25 year old and younger. The Mann-Whitney U test was used to examine the 2 difference in the mathematical skill level 26 of older that 25 to those 25 year old and younger. 8.4 A Wilcoxon test examines the results of the short-distance and medium-distance races. NO significant difference was found A Wilcoxon test examines the results of the short-distance and medium-distance races. NO significant difference was found