# Statistics (13) - 1 Written Assignment 5 Chapter 9 Georgia...

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1 Written Assignment 5 Chapter 9 Georgia Stein Utica College ECM 601 Professor Bing Zhao February 8, 2013
2 1. Use descriptive statistics to summarize the data and comment on your findings. Listed below are the descriptive statistics to be used in making statistical inferences regarding the proportion of business students at Bayview University who were involved in some type of cheating. The aim of the descriptive statistics is to quantitatively summarize the main features of the collection of data. We are given the sample size of the students who participated in the survey. We have the response of interest and the frequency in which it appears in each of the questions being asked in the survey. For example 16 respondents answer “yes” to the question “did you ever present work copied off the internet as your own?” The sample proportion gives us a summary of the percentage of respondents who answered yes to the question. For example 18% of the responders answered yes to the question “did you ever present work copied from the internet as your own?” The confidence interval for all samples is 95%, and the level of significance is 5% The level of significance as it applies here will tell us the probability of making a Type I error. The z value is the test statistic for the hypothesis test about the population proportion. And the standard error indicates how close the sample
3 mean is from the true population. The descriptive statistics are consistent and summarize the data for all three questions in much the same way as described above. The difference being in the number of responders, who answered yes to the questions: “Did you ever copy answers off another student's exam? And, did you ever collaborate with other students on projects that were supposed to be completed individually?” For example there were 18 responders who answered yes to copying answers off another student’s exam, and there were 29 students who answered yes to collaborating with students on projects that were supposed to have been done individually. Because there was a difference in the number of responders who said yes to the first question, and to the second and third, the sample proportions vary. The sample proportion is simply the number of students who answer yes to a question divided by the count, or the number of participants in the survey. For example in answering the first question, there were 16 students who answered yes, and there were 90 participants. The sample proportion is 16/90 or .18, or 18%. The z value can be obtained by dividing the alpha by 2 to get z.025 and then by looking it up in the value worksheet we see that the z value is 1.960, or we can use excel to compute the z value by entering the formula = norm.s.inv and input the appropriate information. For this example we use norm.s.inv (.05/2). To find the standard error we take the square root of the (sample proportion times (1-the sample proportion) and divide it by the sample size).
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