Statistics Practical 2a Comments on Z-tests and t-tests 1. You should have realized from the lectures that in practice, a z-test is seldom used, while the ‘default’ test for single sample or two-samples mean(s) is the ttest. This is because in most practical situations, the population variance is seldom known and therefore we need to estimate that by the sample variance, thus justifying a t-test rather than a z-test. It is always good to perform the standard exploratory data analysis before commencing
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containers, 210 of the voters were opposed. Develop a 92% confidence interval estimate for the proportion of all the voters who opposed the container control bill. Question 2 A random sample of 87 airline pilots had an average yearly income of $99,400 with a standard deviation of $12,000. 1 If we want to determine a 95% confidence interval for the average yearly income, what is the value of t? 2 Develop a 95% confidence interval for the average yearly income of all pilots. Question
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beaches beautiful and our community strong. The confidence interval (also called margin of error) is the plus-or-minus figure usually reported in newspaper or television opinion poll results. For example, if you use a confidence interval of 4 and 47% percent of your sample picks an answer you can be "sure" that if you had asked the question of the entire relevant population between 43% (47-4) and 51% (47+4) would have picked that answer. The confidence level tells you how sure you can be. It is expressed
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found to be 0.2. Give an interval based on your data so that you are 95% confident that the true value of the unknown proportion lies inside it. How would you explain 95% confidence to a layman? Suppose a professor of IIMA thinks that true proportion is 0.3. Are you ready to accept the professor’s perception based on your data at 99% confidence level? Solution – 1 Sample Size n = 100 (male smokers) p = 0.2 Sd (P) = √(pq / n) = .04 95% confidence interval of p = 0.2 ± 2 x 0
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Assignment #1: Bottling Company Case Study By: unknown Instructor: Dr. Unknown Strayer University Course: MAT 300 Date: September 7, 2014 Assignment #1: Bottling Company Case Study Dear Mr. Brooks, Due to multiple customer complaints that we have received, I performed a random testing of the production of our soda pop inventory. I had my team of employees pull a total of 30 bottles off of the assembly line at random; 10 per shift. I also,
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scattergram 2. Construct a 95% confidence interval for the mean GDP per capita. (20 points) 3. Do your data support the hypothesis that more than half of the countries in the world are predominately Christian? (20 points) 4. Determine the sample regression line relating infant mortality to female literacy and plot it on a new scattergram. Test the hypothesis that 1 = 0. Compute a 95% confidence interval estimate for 1. Construct a confidence interval estimate of average infant mortality
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scattergram 2. Construct a 95% confidence interval for the mean GDP per capita. (20 points) 3. Do your data support the hypothesis that more than half of the countries in the world are predominately Christian? (20 points) 4. Determine the sample regression line relating infant mortality to female literacy and plot it on a new scattergram. Test the hypothesis that 1 = 0. Compute a 95% confidence interval estimate for 1. Construct a confidence interval estimate of average infant mortality
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This week there are four discussion topics. Complete by the due date and you will have a second chance to fix mistakes and resubmit for a second review and increased points. Name: DT1 DESCRIPTIVE STATISTICS Please read and understand before responding Topics: Central Tendency, Variability (Dispersion), Quartiles, normal data and skewed distribution of a single data group. You will want to know what measure to use when data distribution is normal (symmetrical) and when the data distribution
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021 2.423 2.704 60 1.296 1.671 2.000 2.390 2.660 120 1.289 1.658 1.980 2.358 2.617 ( 1.282 1.645 1.960 2.326 2.576 MEAN HYPOTHESIS TEST AND CONFIDENCE INTERVAL FORMULAS Null Hypothesis Standard Deviation Data “t” for Hypothesis Test Confidence Interval [pic] [“Previous Standard” is “old” numerical constant to which new statistic is being compared.] DF = n-1 for a small sample. For large sample use last row
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M&Ms® Project Report Rachel Carr Professor Patty Fuller MAT 300- Statistics June 8, 2013 Abstract This paper is about the color proportion of each bag of M&Ms®. Now even though the factory has a claim of the each bag being grouped off into a certain percentage of each color, the results are not always the same. In fact, I will show through random selection process that M&Ms® brand candies each have a different number of candies in the bag and from that a different percentage
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