Math Problem Statement

Solve this

Solution

Let's solve the problem step-by-step.

Part (a): Determine the correlation coefficient

The data provided is:

MovieMinutes Shirtless (x)Opening Weekend Gross (y)
A06.2
B0.68.6
C1.516.6
D2.118.8
E14.122.4

We'll use the formula for the correlation coefficient rr: [ r = \frac{n(\sum xy) - (\sum x)(\sum y)}{\sqrt{[n\sum x^2 - (\sum x)^2][n\sum y^2 - (\sum y)^2]}} ]

Where nn is the number of data points.

First, we calculate the sums and products needed: x=0+0.6+1.5+2.1+14.1=18.3\sum x = 0 + 0.6 + 1.5 + 2.1 + 14.1 = 18.3 y=6.2+8.6+16.6+18.8+22.4=72.6\sum y = 6.2 + 8.6 + 16.6 + 18.8 + 22.4 = 72.6 xy=(0×6.2)+(0.6×8.6)+(1.5×16.6)+(2.1×18.8)+(14.1×22.4)\sum xy = (0 \times 6.2) + (0.6 \times 8.6) + (1.5 \times 16.6) + (2.1 \times 18.8) + (14.1 \times 22.4) =0+5.16+24.9+39.48+316.64=386.18= 0 + 5.16 + 24.9 + 39.48 + 316.64 = 386.18 x2=02+0.62+1.52+2.12+14.12\sum x^2 = 0^2 + 0.6^2 + 1.5^2 + 2.1^2 + 14.1^2 =0+0.36+2.25+4.41+198.81=205.83= 0 + 0.36 + 2.25 + 4.41 + 198.81 = 205.83 y2=6.22+8.62+16.62+18.82+22.42\sum y^2 = 6.2^2 + 8.6^2 + 16.6^2 + 18.8^2 + 22.4^2 =38.44+73.96+275.56+353.44+501.76=1243.16= 38.44 + 73.96 + 275.56 + 353.44 + 501.76 = 1243.16

Now plug these values into the formula: [ r = \frac{5(386.18) - (18.3)(72.6)}{\sqrt{[5(205.83) - (18.3)^2][5(1243.16) - (72.6)^2]}} ] [ r = \frac{1930.9 - 1328.58}{\sqrt{[1029.15 - 334.89][6215.8 - 5271.76]}} ] r=602.32694.26×944.04r = \frac{602.32}{\sqrt{694.26 \times 944.04}} r=602.32655609.4744r = \frac{602.32}{\sqrt{655609.4744}} r=602.32809.67r = \frac{602.32}{809.67} r0.74r \approx 0.74

The correlation coefficient rr is approximately 0.74.

Part (b): Find the equation of the regression line

The equation of the regression line is y=mx+by = mx + b, where: m=n(xy)(x)(y)n(x2)(x)2m = \frac{n(\sum xy) - (\sum x)(\sum y)}{n(\sum x^2) - (\sum x)^2} b=ym(x)nb = \frac{\sum y - m(\sum x)}{n}

Using the values calculated above: m=5(386.18)(18.3)(72.6)5(205.83)(18.3)2m = \frac{5(386.18) - (18.3)(72.6)}{5(205.83) - (18.3)^2} m=1930.91328.581029.15334.89m = \frac{1930.9 - 1328.58}{1029.15 - 334.89} m=602.32694.26m = \frac{602.32}{694.26} m0.87m \approx 0.87

Now calculate bb: b=72.60.87(18.3)5b = \frac{72.6 - 0.87(18.3)}{5} b=72.615.9215b = \frac{72.6 - 15.921}{5} b=56.6795b = \frac{56.679}{5} b11.34b \approx 11.34

Thus, the equation of the regression line is: y=0.87x+11.34y = 0.87x + 11.34

Do you want more details or have any questions?

Questions for you to ask:

  1. How do you interpret the correlation coefficient value in this context?
  2. Can you explain the steps to derive the slope mm of the regression line?
  3. How would you predict the opening weekend gross if the actor appeared shirtless for 5 minutes?
  4. What does the y-intercept bb represent in the regression equation?
  5. How can you assess the strength and direction of a relationship using the correlation coefficient?

Tip:

Always check your calculations step by step to avoid any mistakes, especially when dealing with multiple sums and products in statistical formulas.

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Math Problem Analysis

Mathematical Concepts

Statistics
Correlation Coefficient
Regression Analysis

Formulas

Correlation coefficient formula
Regression line equation

Theorems

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Suitable Grade Level

Higher Education