Question

b) A study wanted to compare the 50 states food expenditures. The researchers measured the amount spent by the state's entire population for food in grocery stores and total amount spent on restaurant food. From their 50 data points (Washington DC not in the study), the researchers calculated a correlation of 0.988. Based on this study, can we say that individuals who spend a lot on groceries also spend a lot at restaurants? What is the lurking variable?

Answer 1

1/2, line rises

we are given the following pair of points and and we are to find the slope of line passing through these points:

(-1, 3) and (3, 5)

slope =
`\frac {y_2 - y_1} {x_2 - x_1}` =
`\frac{5-3} {3--1}` =
`\frac{2} {4}` =
`\frac{1} {2}`

the slope of this line is 1/2 which is positive so the line rises from bottom left towards top right.