Data
Tire pressure/ psi
33
35
31
34
27
25
31
28
30
33
30
31
29
32
28
Mean from frequency distribution
Grade bins	Freq	RF or P(x)	x*p(x)
168	112	__________	__________
316	658	__________	__________
464	1172	__________	__________
612	332	__________	__________
760	123	__________	__________
Sums:	_____	__________	__________
Linear regression
Pressure/PSI	Load/lbs
20	992
23	1062
26	1123
29	1183
32	1243
35	1302