Question-1 a) Compute the value of correlation coefficient of using data in table 1 for the number of hrs. a person works per week and the number of accidents or injuries that the person has over a peroid of one week. [4 marks] b) Identify the type of correlation in this case. [0.5marks] c) when we can say that there is no correlation or very weak correlation [0.5marks] Table : 1 Hrs.Worked No. of accidents (x) (y) 40 1 32 0 36 3 44 8 41 5
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$$ \bar{x} = \frac{40 + 32 + 36 + 44 + 41}{5} = 38.6 $$ $$ \bar{y} = \frac{1 + 0 + 3 + 8 + 5}{5} = 3.4 $$ Show more…
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Jon S.
1.) If the correlation between age of an auto and money spent for repairs is +.90 a) 81% of the variation in the money spent for repairs is explained by the age of the auto b) 81% of money spent for repairs is unexplained by the age of the auto c) 90% of the money spent for repairs is explained by the age of the auto d) none of the above 2.) The correlation coefficient for X and Y is known to be zero. We then can conclude that: a) X and Y have standard distributions b) the variances of X and Y are equal c) there exists no relationship between X and Y d) there exists no linear relationship between X and Y e) none of these 3.) What would you guess the value of the correlation coefficient to be for the pair of variables: "number of man-hours worked" and "number of units of work completed"? a) Approximately 0.9 b) Approximately 0.4 c) Approximately 0.0 d) Approximately -0.4 e) Approximately -0.9
Adi S.
Question 6.2 A study was conducted to determine the effect of extra help sessions attended on student’s ability to avoid mistakes on a 20- multiple choice test. The data shown below represent the number of extra help sessions attended(x) and the average number of mistakes (y) recorded. x | 1 | 2 | 3 | 4 | 5 | 6 y | 6.1 | 5.1 | 5.0 | 4.2 | 3.7 | 3.2 ∑x_i = 21 ∑y_i = 27.3 ∑x_iy_i = 85.8 ∑x_i^2 = 91 ∑y_i^2 = 129.79 n = 6. a) Calculate the sample correlation coefficient. Describe the relationship between the number of extra help sessions attended and the average number of mistakes recorded. Calculate the sample correlation coefficient. b) Find the best fitting line relating the number of extra help sessions attended and the average number of mistakes recorded. c) Interpret the slope of this line in the context of the problem. d) What is the estimated number of mistakes recorded when the number of extra help sessions is 5. e) Circle your answer, either true or false, for each question. 1. Regression procedures are appropriate for studying a relationship between two categorical variables. True False 2. Correlation/association implies causation. True False 3. Correlation coefficients (correlations) range from -1 to 1. True False 4. If a correlation is close to 0, it means there is no relationship between X and Y. True False
Madhur L.
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