
Tire pressure/psi 


33 

35 

31 

34 

27 

25 

31 

28 

30 

33 

30 

31 

29 

32 

28 
1 
ratio 
What level of measurement is tire pressure in pounds per square inch? 




2 
15 
Find the sample size n for the tire pressure data. 




3 
25 
Find the minimum tire pressure. 




4 
35 
Find the maximum tire pressure. 




5 
10 
Find the range of the tire pressure. 




6 
31 
Find the median tire pressure. 




7 
31 
Find the mode for the tire pressure. 




8 
30.47 
Find the sample mean tire pressure. 




9 
2.75 
Find the sample standard deviation for the tire pressure. 




10 
0.0902 
Find the sample coefficient of variation CV. 




11 
2 
Width 




12 
Bins (x) 
Frequency (f) 
Rel. Freq. p(x) 




27 
2 
0.133 




29 
3 
0.200 




31 
5 
0.333 




33 
3 
0.200 




35 
2 
0.133 




Sum: 
15 
1 



13 
Sketch a relative frequency histogram 





14 
symmetric 
What is the shape of the distribution? 





Calculation of Mean from Frequency Table 






Mean from frequency distribution Grade bins 
Freq 
RF or P(x) 
x*p(x) 



168 
112 
0.05 
7.85 



316 
658 
0.27 
86.75 



464 
1172 
0.49 
226.87 



612 
332 
0.14 
84.77 



760 
123 
0.05 
39 



Sums: 
2397 
1 
445.23 


15 
445.23 
What is the mean grade for the 2397 tires? 





Linear regression 






Linear regression Pressure/PSI 
Load/lbs 





20 
992 





23 
1062 





26 
1123 





29 
1183 





32 
1243 





35 
1302 




16 
20.5 
Calculate the slope of the linear trend line. 




17 
586.95 
Calculate the yintercept for the data. 




18 
positive 
Is the correlation positive, negative, or neutral? 




19 
0.9996 
Determine the correlation coefficient r. 




20 
high (or perfect) 
Is the correlation none, low, moderate, high, or perfect? 




21 
linear 
Does the relationship appear to be linear or nonlinear? 




22 
0.9992 
Determine the coefficient of determination. 




23 
99.92% 
What % in the variation in pressure variable accounts for the variation in load? 




24 
1099.57 
A tire with an inflation of 25 psi could be expected to bear what load in pounds? 




25 
33.99 
A load of 1284 pounds would require what inflation pressure? 




26 
Tire would blow 
A tire with an inflation of 100 psi could be expected to bear what load in pounds? 





Normal curves 





27 
C 
Which of the following curves is a normal curve? 





For the following normal distribution determine: 





28a 
5.5 
What is the mean? 




28b 
2.2 
What is the standard deviation? 























