Question
Movie companies need to predict the gross receipts of individual movies after a movie has debuted....
Movie companies need to predict the gross receipts of individual movies after a movie has debuted. The accompanying results are the first weekend gross, the national gross, and the worldwide gross (in millions of dollars) of six movies. Complete parts (a) through (d) below..
a. Compute the covariance between first weekend gross and national gross, first weekend gross and worldwide gross, and national gross and worldwide gross.
QUESTION 1: Find the covariance between first weekend gross and national gross. nothing (Round to four decimal places as needed.)
Title First Weekend National Gross Wordwide Gross
Movie A 90.868 317.036 976.867
Movie B 88.947 261.469 878.796
Movie C 93.682 249.394 795.296
Movie D 102.506 290.303 896.347
Movie E 77.133 292.853 938.099
Movie F 77.965 301.232 934.742
Answers
We will calculate the sample covariances, as the data we have is a sample of 6 movies.
Sample covariance between 2 variables X and Y is calculated as (we will use n-1 as the denominator, as against "n" in case of population covariance)
where n is the number of observations
is the sample mean of X
is the sample mean of Y
Let X be the First Weekend gross
Y be the National gross
Z be the worldwide gross
The sample means are
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a) the sample covariance between first weekend gross (X) and national gross (Y) is
ans: The sample covariance between first weekend gross and national gross is -61.0403
the sample covariance between first weekend gross (X) and worldwide gross (Z) is
ans: the sample covariance between first weekend gross and worldwide gross is -244.1229
The sample covariance between national gross (Y) and worldwide gross (Z) is
ans: The sample covariance between national gross and worldwide gross is 1505.1251