Assessing T-tests To clearly identify what a t-test accomplishes in descriptive statistics it is imperative to understand what a t-test represents. A “t-test is a parametric statistical test for comparing the means of two independent samples” (Plichta & Kelvin‚ 2013‚ p. 464). Gosset developed the t-test for use in quality control at the Guinness Brewery and published his works under the pen name “Student” (Plichta & Kelvin‚ 2013). T-tests use assumptions related to the underlying
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TEST REVIEW – We will work these problems in class. Data Files for these problems will be disclosed in class during the review. On TEST 3‚ you will be asked to perform hypothesis tests‚ find confidence intervals‚ and conduct regression analyses. Be prepared to also interpret information on any Excel print-outs. Test 3 will be a multiple-choice test. 1. A federal agency responsible for enforcing laws governing weights and measures n=1 routinely inspects packages to determine whether the
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middle of a distribution of numbers‚ such that half the cases are higher and half lower than a value. What statistical measure should he use? A. mean B. median* C. mode D. standard deviation 3. A "codebook" is A. only used in existing statistics research. B. a document that tells the researcher where variables are located in the data file and what numbers go with variable attributes* C. the set of instructions that tell interviewers or experimenters how to treat respondents or subjects
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Sample Paper Mid Term Examination All questions carry equal marks (4 Marks Each) Q.No. 1 a) i) Suppose you are an operations manager for a plant that manufactures batteries. Give an example how you could use descriptive statistics to make better managerial decisions. ii) Listed here are 30 different weekly Dow Jones industrial stock averages. 2656 2301 2975 3002 2468 2742 2830 2405 2677 2990 2200 2764 2337 2961 3010 2976 2375 2602 2670 2922 2344 2760 2555 2524 2814 2996 2437 2268 2448 2460 Construct
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your work for full credit. All answers must be supported by correct work to receive full credit. SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question. Solve the problem. 1) Multiple-choice questions on a test each have 4 possible answers‚ one of which is correct. Assume that you guess the answers to 4 such questions. a. Use the multiplication rule to find the probability that the first two guesses are wrong and the third and fourth guesses are correct.
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Last name: First name: Student #: STA 304H1 F/1003H F SUMMER 2009‚ First Test‚ May 28 (20%) Duration: 50min. Allowed: hand-calculator‚ aid-sheet‚ one side‚ with theoretical formulas and definitions only. [25] 1) A marketing analyst is asked to study the buying habits of shoppers at a national chain store (e.g. Sears). Suppose there are 150 stores around the country. (a) Describe the population of interest. (b) Describe in short a realistic sampling procedure for obtaining a representative
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1. A recent issue of Fortune Magazine reported that the following companies had the lowest sales per employee among the Fortune 500 companies. [20 Marks] | |Company |Sales per Employee ($1000s) |Sales Rank | | |Seagate Technology |$42.20 |285 | | |SSMC | 42.19
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straight line‚ positive slope. / R=-1 fall along a straight line with a negative slope. \ R=0 no linear relationship between variables. --- Limits on correlation coefficients- can only use if both are interval‚ and sensitive to outliers‚ does not capture non-linear relationships‚ does not show the strength of relationships. Interquartile range- location measure‚ shows outliers. Regression- how close the value is to the line (r^2) y=a+bx a= intercept. B= slope. Intercept is y=? when x=0. Regression line
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Elements of a Test of Hypothesis 1. Null Hypothesis (H0 ) - A statement about the values of population parameters which we accept until proven false. 2. Alternative or Research Hypothesis (Ha )- A statement that contradicts the null hypothesis. It represents researcher’s claim about the population parameters. This will be accepted only when data provides sufficient evidence to establish its truth. 3. Test Statistic - A sample statistic (often a formula) that is used to decide whether to reject H0
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Test 8A A P Statistics Name: Directions: Work on these sheets. A random digit table is attached. Part 1: Multiple Choice. Circle the letter corresponding to the best answer. 1. In a large population of college students‚ 20% of the students have experienced feelings of math anxiety. If you take a random sample of 10 students from this population‚ the probability that exactly 2 students have experienced math anxiety is (a) 0.3020 (b) 0.2634 (c) 0.20 13 (d) 0.5 (4 1 (f) None of
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