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Homework 4
Name: ID# Section
1 A medical researcher wishes to see if there is a relationship between prescription drug prices for identical drugs and identical dosages that are prescribed for humans and for animals. The prices are shown. Is there a relationship between the prices?
Prices for humans (x) 0.67 0.64 1.20 0.51 0.87 0.74 0.50 1.22 Prices for animals (y) 0.13 0.18 0.42 0.25 0.57 0.57 0.49 1.28 a. Draw the scatter plot for the variables.
b. Compute the value of the correlation coefficient.
c. Give a brief explanation of the type of relationship.
d. Find the equation of the regression line and predict the prescription drug price for animals when the price for humans is 0.75.
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2 A hospital administrator wants to see if there is a relationship between the number of licensed beds and the number of staffed beds in local hospitals. The data for a specific day are shown. Describe the relationship.
Licensed beds (x) 144 32 175 185 208 100 169 Staffed beds (y) 112 32 162 141 103 80 118 a. Draw the scatter plot for the variables.
b. Compute the value of the correlation coefficient.
c. Give a brief explanation of the type of relationship.
d. Find the equation of the regression line and predict the number of staffed beds when the number of licensed beds is 44.
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3 Complete the following statements with the best answer.
a. A statistical graph of two variables is called a(n) .
b. The x variable in the equation of the regression line is called the variable.
c. The range of r is from to .
d. The sign of r and will always be the same.
e. The regression line is called the .
f. If all the points fall on a straight line, the value of r will be or .
4 The table shows the average maximum sentence length for certain crimes and the actual time served in months. Is there a relationship between the two?
Crime Murder Rape Robbery Burglary Drug offenses Weapons offenses Sentence 227 120 106 77 60 49
Time served 97 45 40 26 18 21
5 Six different summer theater actors were ranked by male and female patrons on the basis of diction and appearance. The data are shown here (1 is the highest rating). Is there a relationship between the rankings?
Actors A B C D E F Males 6 3 2 5 1 4 Females 4 5 1 6 3 2
