Directions: Read carefully. These questions pertain to linear regressions.

1.  The relationship between the number of widgets in a package and the length of the package, in inches, is given in the table at the right.
a) What is the slope of the line of best fit (linear regression)?
(Widgets on x-axis, Length on y-axis)
Choose:
 0.25 0.5 0.75 1
 Number of Widgets Length of Package (in.) 3 9.00 4 9.25 5 9.50 6 9.75    MB

b) What is the value of the y-intercept of the linear regression?
Choose:
 9 8.75 8.5 8.25

2.  The table below shows the relationship between total fat grams and the total calories in a selection of fast food sandwiches. Find the linear regression equation that models this data. (Round to nearest integer with Fat on x-axis and Calories on y-axis.)
Choose:
 y = 14x + 99 y = 14x + 98 y = 13x + 143 y = 13x + 142
 Total Fat (g) 9 13 21 30 31 32 34 Total Calories  MB 260 320 420 530 560 580 590

3.  During a solar eclipse, the temperature begins to drop as the Moon comes between the Earth and the Sun. The cooling temperatures, up through totality, of the eclipse are shown. Using a linear regression equation, predict the temperature at the 4 minute mark during the cooling, to the nearest degree. (Use this same cooling pattern.)
Choose:
 60º 59º 58º 57º
Eclipse Temperature Drop
in the viewing city.

 MB  Time      (minutes) Temp. º F. 0 75 1 71 2 66 3 62 4 ?

4.  A morning radio talk show is running a "Winter Coat Campaign" to collect and deliver coats to local shelters. They are storing the coats until they reach their goal of 2100 coats. The table at the right shows the number of coats in storage at the end of each day of the campaign.
a) Which equation is the linear regression equation for this data
(rounded to nearest hundredths with Days on x-axis and Coats on y-axis)?
 Day of Campaign Number of Coats Stored 1 860 2 930 3 1000 4 1150 5 1200 6 1360    MB
Choose:
 y = 98.86 + 737.33x y = 98.86x + 737.33 y = 97.76 + 737.33x y = 97.76x + 737.33
b) Using the equation from part a, predict the day the campaign will meet its goal and the coats will be delivered to the shelters.
Choose:

 Day 10 Day 12 Day 14 Day 16

5.  A store is doing inventory for one week to determine the popularity of a new product.
 Day Number 1 2 3 4 5 6 7 Number sold   MB 24 32 41 50 60 68 77
 a) Find the linear regression equation that models this data. (Round to nearest integer.) Choose: y = 8x +14 y = 9x +15 y = 15x +9 y = 14x +8
 b) If this pattern of growth continues, predict the number sold on the 10th day. Choose: 94 105 148 159