Question

Find the mean and standard deviation of the times and icicle lengths for the data on run 8903 in data data168.dat. Find the correlation between the two variables. Use these five numbers to find the equation of the regression line for predicting length from time. Use the same five numbers to find the equation of the regression line for predicting the time an icicle has been growing from its length. (Round your answers to three decimal places.)

time    length
10      3.3
20      .6
30      3.8
40      6.7
50      8.7
60      10.6
70      10.1
80      12.4
90      15.3
100     14.1
110     17.4
120     18.2
130     19.7
140     23.1
150     23.7
160     27.9
170     27.9
180     29.4

times x =
times s =
lengths x =
lengths s =
r =
time =	______ +______ length
length =	______ +______ time

Answer 1

Let X be length and Y be time

        (Round to 4 decimal)

Mean for length = 15.1611    

Mean for time = 95

Standard deviation for length = 8.906   (Round to 3 decimal)

Standard deviation for time = 53.385    (Round to 3 decimal)

Correlation coefficient:

r = 0.990

Correlation coefficient = r = 0.990

Regression equation is

Where

and

             = 95 - 5.937 * 15.1611

            = 95 - 90.01145

            = 4.988

Regression equation is

time = 4.988 + 5.937 * length