The table shows hours studied and test scores for five students. Plot a scatter plot, describe the correlation, draw a line of best fit, find the regression equation, predict a score, and explain regression analysis.

Mathematics
The table shows hours studied and test scores for five students. Plot a scatter plot, describe the correlation, draw a line of best fit, find the regression equation, predict a score, and explain regression analysis.

ScanSolve AI Answer

1.2.1 Scatter plot points: (2,50)(2, 50), (6,65)(6, 65), (8,85)(8, 85), (10,90)(10, 90).

1.2.2 The scatter plot shows a strong positive linear correlation. As hours studied increase, test scores increase nearly linearly with little scatter around an upward trend.

1.2.3 The intuitive line of best fit passes close to all points with a positive slope approximately 55. It roughly follows from near (2,50)(2, 50) through (6,65)(6, 65) and (10,90)(10, 90), balancing distances above and below.

1.2.4 Equation of the regression line y=mx+cy = mx + c.

Step 1: Data and sums table.

xyx2xy250410066536390885646801090100900x=26y=290x2=204xy=2070\begin{array}{|c|c|c|c|} \hline x & y & x^{2} & xy \\ \hline 2 & 50 & 4 & 100 \\ 6 & 65 & 36 & 390 \\ 8 & 85 & 64 & 680 \\ 10 & 90 & 100 & 900 \\ \hline \sum x = 26 & \sum y = 290 & \sum x^{2} = 204 & \sum xy = 2070 \\ \hline \end{array}

Step 2: Slope formula

m=nxy(x)(y)nx2(x)2m = \frac{n \sum xy - (\sum x)(\sum y)}{n \sum x^{2} - (\sum x)^{2}}

where n=4n=4.

Substitute values:

m=4×207026×2904×204262=82807540816676=740140=377.m = \frac{4 \times 2070 - 26 \times 290}{4 \times 204 - 26^{2}} = \frac{8280 - 7540}{816 - 676} = \frac{740}{140} = \frac{37}{7}.

Step 3: Intercept formula

c=ymxn.c = \frac{\sum y - m \sum x}{n}.

Substitute:

mx=377×26=37×267=9627,m \sum x = \frac{37}{7} \times 26 = \frac{37 \times 26}{7} = \frac{962}{7}, ymx=2909627=20309627=10687,\sum y - m \sum x = 290 - \frac{962}{7} = \frac{2030 - 962}{7} = \frac{1068}{7}, c=1068/74=106828=2677.c = \frac{1068/7}{4} = \frac{1068}{28} = \frac{267}{7}.

Regression line: y=377x+2677y = \frac{37}{7}x + \frac{267}{7} or approximately y=5.29x+38.14y = 5.29x + 38.14.

y = \frac{37{7}x + \frac{267}{7}}

1.2.5 For x=7x=7 hours studied,

y=37×7+2677=259+2677=526775.14.y = \frac{37 \times 7 + 267}{7} = \frac{259 + 267}{7} = \frac{526}{7} \approx 75.14.

Predicted test score: 75.

75

1.2.6 Regression analysis finds the line of best fit that minimizes the sum of squared residuals (differences between observed and predicted yy-values). This provides the most accurate linear model for the data, enabling reliable predictions for xx-values within the observed range (e.g., 2 to 10 hours).

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