# Paper Writing Services interval. 8. What assumption do you need to make about the population of interest to construct the confidence intervals? Problem 2 (25

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so, how? 5. Based on the previous results what conclusions can you reach concerning the price of digital cameras at a camera specialty store during 2014. 6. Construct a 90%, 95%, 99% confidence interval for the population mean cost of digitals cameras. 7. Interpret the meaning of each interval. 8. What assumption do you need to make about

Problem 1 (25 pts) The cost of 14 models of digitals cameras at a camera specialty store during 2014 was as follows: 340 450 450 280 220 340 290 370 400 310 340 430 270 380 1. Compute mean, median, mode, first and trd quartile.   2. Compute the variance, standard deviation, range, interquartile range, coefficient of variation, standard error of the mean and Z scores.   3. Determine whether or not there are outliers? Explain.  4. Determine whether or not the data are skewed? If so, how?   5. Based on the previous results what conclusions can you reach concerning the price of digital cameras at a camera specialty store during 2014.   6. Construct a 90%, 95%, 99% confidence interval for the population mean cost of digitals cameras.   7. Interpret the meaning of each interval.   8. What assumption do you need to make about the population of interest to construct the confidence intervals? Problem 2 (25 pts) Consider the sample data for plants A, B, C & D of the above company, wch are  tabulated in table 1. Test whether the four means are equal at the 5% level of significance. Perform a test that will compare all 4 means at once. We are not interested in pair-wise comparisons at ts stage. Please show all the steps in your calculations. Table 1:  A    B    C    D  333 328 320 333 332 329 321 321 320 323 322 329 326 327 325 330 328 330 326 328 325 331 328 325 323 332 329 333 321 320 330 331 334 324 331 327 322 323 332 320 334 329 330 328 331 330 Problem 3 (25 pts) The camera store in question wants to increase sales and is exploring three options: 1. Invest and expand the current store. 2. Open a second store in another part of the city. 3. Open an online outlet. Develop a methodology including the statistical methods used to assess between these options. Problem 4 (25 pts) Read the article (p. 221 – 225)  «Performance and duration differences between online and paper–pencil tests» and answer the questions below. Part A. 1. Develop a 95% confidence interval using data from ts study.   2. Perform a hypothesis testing using data from ts study. (show all the the appropriate steps).   3. Suggest another statistical technique(s) for the purpose of ts study. Explain. Part B.  For ts study briefly describe how the researcher draw conclusions from a sample about a population. Try to be as analytic as possible and use the comments bellow.

Sample references
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