Question

Statistics students in Oxnard College sampled 9 textbooks in the Condor bookstore and recorded the number of pages in each textbook and its cost. The data are shown below:

Number of Pages (xx)	Cost(yy)
359	31.95
865	59.25
554	38.7
966	51.3
782	61.1
733	58.65
209	19.45
697	49.85
582	46.1

A student calculates a linear model using technology (Statistics Calculator or Computer)
ˆyy^ =  xx + . (Please show your answers to two decimal places)
Use the model to estimate the cost when number of pages is 874.
Cost = $ (Use the linear model with yor rounded coefficients and then round your answer to 2 decimal places.)

Answer 1

Find X⋅Y and X² as it was done in the table below.

X	Y	X⋅Y	X⋅X
359	31.95	11470.05	128881
865	59.25	51251.25	748225
554	38.7	21439.8	306916
966	51.3	49555.8	933156
782	61.1	47780.2	611524
733	58.65	42990.45	537289
209	19.45	4065.05	43681
697	49.85	34745.45	485809
582	46.1	26830.2	338724

• Answer : Y hat = 0.05 x + 12.90

Given x = 874 then

y = 0.05 ( 874 ) + 12.90

=56.6

• Answer : Cost (y ) = $ 56.60