Concept explainers
Sketch the graphs of the following pdfs and find and sketch the graphs of the cdfs associated with these distributions (note carefully the relationship between the shape of the graph of the
(a)
(b)
(c)
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Probability And Statistical Inference (10th Edition)
- Assume that you have collected cross-sectional data for average hourly earnings (ahe), the number of years of education (educ) and gender of the individuals (you have coded individuals as "1" if they are female and "0" if they are male; the name of the resulting variable is DFemme). Having faced recent tuition hikes at your university, you are interested in the return to education, that is, how much more will you earn extra for an additional year of being at your institution. To investigate this question, you run the following regression: ahe= -4.58 + 1.71×educ N = 14,925, R2 = 0.18, SER = 9.30 a. Interpret the regression output. b. Being a female, you wonder how these results are affected if you entered a binary variable (DFemme), which takes on the value of "1" if the individual is a female, and is "0" for males. The result is as follows ahe= = -3.44 - 4.09×DFemme + 1.76×educ N = 14,925, R2 = 0.22, SER = 9.08 Does it make sense that the standard error of the regression decreased…arrow_forwardFor a correlation of -.64 between X and Y, each 1 _SD change in Zx corresponds to a predicted change of _____________SD in Zy.arrow_forwardA correlation of r = .85 is found between weekly sales of firewood and coughdrops over a 1-year period. Which of the following is true? (a) There is a pretty strong positive linear relationship between sales of firewood and cough drops. (b) Fire must be the cause of coughing. (c) Temperature is a possible lurking variable that is “behind” this relationship. (d) Both (a) and (c) are true. (e) None of the above.arrow_forward
- Kahl Co wants to know whether there is a correlation between the number of labour hours worked (x) and the value of factory overheads (y). The following figures have been calculated: [x 89 1,063 1,047 150,251 12,475 8 Exy n Which of the following statements is/are correct? (1) The correlation coefficient is 0.9 (to one decimal place) (2) 90% of the variation in factory overheads is explained by changes in the number of labour hours worked 2 only [x² 01 only Both 1 and 2 Neither 1 nor 2arrow_forwardRandom variables X and Y have the joint PMF with a constant k (kxy, х — P(x,y) = { 0, 1,4; y = 1,3 otherwise Find thearrow_forwardCompute the value of correlation coefficient of using data in table 1 for the number of hrs. a person works per week and thenumber of accidents or injuries that the person has over a peroid of one week. Table :1 Hrs.Worked ( x ) No. of accidents( y ) 30 2 42 3 25 4 44 8 56 5arrow_forward
- A correlation of r = .79 is found between weekly sales of firewood and cough drops over a 1-year period. Which of the following is true? (a) There is a pretty strong positive linear relationship between sales of firewood and cough drops. (b) Fire must be the cause of coughing. (C) Temperature is a possible lurking variable that is behind this relationship. (d) Both (a) and (c) are true. (e) None of the above.arrow_forwardA study was done to investigate the relationship between amount of protix (a new protein-vitamin•-mineral supplement) org a fortified- vitamin rice, known as FVR, and the gain in weight of children. Ten randomly chosen sections of grade one pupils were fed with FVR containing protix; different amounts X of protix were used for the 10 sections. The increase in the weight of each child was measured after a given period. The average gain Y in weight for each section with a prescribed protix level x is as follows; Section(i) Protix(X) Gain(Y) Section(i) Protix(X) Gain(Y) 1 2 3 4 5 50 60 70 80 90 91.6 96.5 95.5 101.3 104.8 6 7 8 9 10 100 110 120 130 140 105.2 107.9 107.4 109.2 109.8 Compute the prediction equation to predict the gain in the weight of a child.arrow_forwardA correlation of r=0.85 is found between weekly sales of firewood and cough drops over a 1-year period. Which of the following is true? (a) There is a pretty strong positive linear relationship between sales of firewood and cough drops. (b) Fire must be the cause of coughing. (c) Temperature is a possible lurking variable that is behind this relationship. (d) Both (a) and (c) are true. (e) None of the above.arrow_forward
- Calculus For The Life SciencesCalculusISBN:9780321964038Author:GREENWELL, Raymond N., RITCHEY, Nathan P., Lial, Margaret L.Publisher:Pearson Addison Wesley,Algebra & Trigonometry with Analytic GeometryAlgebraISBN:9781133382119Author:SwokowskiPublisher:Cengage