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##### Northcentral Statistics in Educational Research Problems

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Question;Northcentral UniversityData File 4/Statistics in Educational ResearchData File 4Show all your workChapter SevenProblem 1) Look at the scatter plot below. Does it demonstrate a positive or negativecorrelation? Why?Is there any outliers? What are they?Problem 2) Look at the scatter plot below. Does it demonstrate a positive or negativecorrelation? Why?Is there any outliers? What are they?Problem 3) The following data come from your book, problem 26 on page 298. Here isthe data:Mean daily caloriesInfant Mortality Rate (per 1,000 births)152315434956194111426782416101073443616401533362734294426717a) For the above data construct a scatter plot using SPSS or Excel(Follow instructions on page 324 of your textbook). What does thescatter plot show? Can you determine a type of relationship? Arethere any outliers that you can see?b) Using the same data conduct a correlation analysis using SPSS orExcel. What is the correlation coefficient? Is it a strong, moderate orweak correlation? Is the correlation significant or not? If it is whatdoes that mean?Problem 4)Bill is doing a project for you in the marketing department. In conducting hisanalysis regarding consumer behavior and a new product that has come out, hetells you the correlation between these two variables is 1.09. What is yourresponse to this analysis?Problem 5)Judy has conducted an analysis for her supervisor. The results she obtained was acorrelation coefficient that was negative 0.86. Judy is confused by this numberand feels that because it is negative and not positive, is means that it is bad. Youare here supervisor. How would you clarify this result for Judy regarding themeaning of the correlation?Problem 6)Explain the statement, correlation does not imply causality.Problem 7)Using the best-fit line below for prediction, answer the following questions:a) What would you predict the price of Product X in volume of 150 to be(approximately)?b) What would you predict the price of Product X in volume of 100 to be(approximately)?Problem 8)You are interested in finding out if a students ACT score is a good predictor of theirfinal college grade point average (GPA). You have obtained the following data and aregoing to conduct a regression analysis. Follow instructions on page 324 of your textbookunder line of best fit to conduct this analysis?ACTGPA22.03.032.03.7833.03.6821.02.9427.03.3825.03.2130.03.65a) What is the R? What type of relationship does it indicate (strong/weak,positive/negative)?b) Go to the coefficients readout. The constant is the intercept. Under that is the ACTand that is the slope. Using the straight line formula of Y = mx + b, which you willfind on page 313, you will now predict some future GPA scores: In the formula (m)is the slope, (x) is the variable that you are looking to use as a predictor, and (b) is theintercept. Predict GPA from the following ACT scores using the regressionequation/straight line formula (show all your work):1) 202) 253) 34Data File 4/Statistics in Educational ResearchShow all your workProblem 1)A sample of nine students is selected from among the students taking a particular exam.The nine students were asked how much time they had spent studying for the exam andthe responses (in hours) were as follows:18, 7, 10, 13 12, 16, 5, 20, 21Estimate the mean study time of all students taking the exam. Round your answer to thenearest tenth of an hour, if necessary.Problem 2)Scores on a particular test have a mean of 64.6. The distribution of sample means forsamples of size 100 is normal with a mean of 64.6 and a standard deviation of 1.9.Suppose you take a sample of size 100 of test scores and find that the mean is 63. Whatis the z-score corresponding to this sample mean?Problem 3)There are 349 teachers at a college. Among a sample of 110 teachers from this college,66 have doctorates. Based on this sample, estimate the number of teachers at this collegewithout doctorates.Problem 4)Sample size = 400, sample mean = 44, sample standard deviation = 16. What is themargin of error?Problem 5)A sample of 64 statistics students at a small college had a mean mathematics ACT scoreof 28 with a standard deviation of 4. Estimate the mean mathematics ACT score for allstatistics students at this college. Give the 95% confidence interval.Problem 6)A government survey conducted to estimate the mean price of houses in a metropolitanarea is designed to have a margin of error of $10,000. Pilot studies suggest that thepopulation standard deviation is $70,000. Estimate the minimum sample size needed toestimate the population mean with the stated accuracy.Problem 7)A researcher wishes to estimate the proportion of college students who cheat on exams.A poll of 490 college students showed that 33% of them had, or intended to, cheat onexaminations. Find the margin of error for the 95% confidence interval.

Paper#61488 | Written in 18-Jul-2015

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