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Use this information to fill in all values in an analysis of variance for regression table as shown. $$ \begin{array}{|l|l|l|l|l|l|} \hline \text { Source } & \text { df } & \text { SS } & \text { MS } & \text { F-statistic } & \text { p-value } \\ \hline \text { Model } & & & & & \\ \hline \text { Error } & & & & & \\ \hline \text { Total } & & & & & \\ \hline \end{array} $$ SSModel \(=800\) with SSTotal \(=5820\) and a sample size of \(n=40\)

Short Answer

Expert verified
The completed Analysis of Variance (ANOVA) for regression table is:\[\begin{array}{|l|c|c|c|c|c|}\hline \text{Source} & \text{df} & \text{SS} & \text{MS} & \text{F-statistic} & \text{p-value} \ \hline \text{Model} & 1 & 800 & 800 & 6.055 & ? \ \hline \text{Error} & 38 & 5020 & 132.105 & & \ \hline \text{Total} & 39 & 5820 & & & \ \hline \end{array} \]

Step by step solution

01

Calculate Degrees of Freedom (df)

Degrees of Freedom (df) refers to the number of independent pieces of information that went into the calculation of an estimate. Generally, in a regression table, df for Model is \(k-1\), df for Error is \(n-k\), and df for Total is \(n-1\). Here, where the sample size \(n = 40\), and the regression is a simple linear regression (only one predictor), so \(k = 2\).Therefore df for the model would be \(k-1 = 2-1 = 1\), df for the error would be \(n-k = 40-2 = 38\), df for the Total would be \(n-1 = 40-1 = 39\).
02

Calculate Remaining Sum of Squares (SSError)

The Sum of Squares Error (SSError) is the sum of the squared differences between the predicted and actual observation. It's represented as the SSTotal - SSModel. In this case, SSError would be 5820 (SSTotal) - 800 (SSModel) = 5020.
03

Calculate Mean Sum of Squares (MS)

The Mean Sum of Squares (MS) is the average sum of squared errors. It can be calculated as the SS divided by its degree of freedom (df).Here, MS for Model = SSModel/dfModel = 800/1 = 800, MS for Error = SSError/dfError = 5020/38 = approximately 132.105.
04

Calculate F-statistic

The F-statistic is the ratio of the Model Mean Square to the Error Mean Square. So, F-statistic would be MSModel/MSError = 800/132.105 = approximately 6.055.
05

Calculate p-value

The p-value is determined from the F-statistic value and corresponding degrees of freedom using an F-distribution table or statistical software. Since the p-value calculation usually involves complex calculations or the use of a statistics software, it is not feasible to compute in this context. We can denote it with '?' for the purposes of this exercise.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Degrees of Freedom (df)
When diving into statistical analysis, the concept of Degrees of Freedom (df) is essential to understand. It refers to the number of independent values or quantities that can vary in an analysis without breaking any constraints. In the context of regression analysis, the df for the model, error, and total helps set the stage for further calculations and interpreting results.

For the model df, we subtract one from the number of predictors, including the intercept, since we're estimating parameters. For error df, we consider the total sample size minus the number of estimated parameters. Lastly, the total df is simply one less than our sample size because we're using one piece of data to estimate the mean. Understanding these intricacies allows for correct set up in an analysis of variance for regression.
Sum of Squares (SS)
The Sum of Squares (SS) holds a key role in understanding variability within your data. Essentially, it's a measure of the total variation in the dataset. When we calculate SS, we're squaring the difference between each observed value and the mean (for total SS) or the predicted values (for model SS), then summing all those squared values.

There are different types of SS in regression analysis – the SS of the model indicates how well the model explains the data, while the SS of the error shows how much variation is unexplained by the model. In the given exercise, we've seen how the SS for the model and SS for error add up to the total SS, which represents all variation in the data, both explained and unexplained.
Mean Sum of Squares (MS)
Once we grasp the concept of SS, we can move on to the Mean Sum of Squares (MS), which is derived by dividing the SS by their corresponding df.

It's the average square of these deviations and is crucial for comparing models. This calculation allows us to assess whether the model significantly reduces the error when predicting our dependent variable. In other words, we can see how well our model performs by looking at how much the MS for the model deviates from the MS of the error. The given problem shows the direct application by dividing SS of Model and Error by their respective df's to obtain their MS values.
F-statistic
The F-statistic is a powerful test statistic that comes into play when comparing statistical models. It is calculated by dividing the MS of the model by the MS of the error.

This ratio tells us if the additional complexity of our model is justified by a significant reduction in residuals or unexplained variance. A high F-statistic signifies that the model explains a significant portion of the variance in the data, which in turn suggests that the model is a good fit. It's how we quantitatively decide if our model is significantly better than the baseline or not, making it a cornerstone of regression analysis.
p-value
Last but not least, we have the p-value, which might just be the most recognized term in statistical hypothesis testing. The p-value tells us about the likelihood or probability of observing our results (or more extreme) given that the null hypothesis is true.

In the context of ANOVA and regression, it helps us determine whether the patterns found in the sample data are strong enough to be considered statistically significant in the population. A small p-value (typically ≤ 0.05) indicates that there is strong evidence against the null hypothesis, leading us to reject it. In other words, if our F-statistic is significantly high, the corresponding p-value helps confirm whether our findings are likely to be valid.

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Most popular questions from this chapter

We show an ANOVA table for regression. State the hypotheses of the test, give the F-statistic and the p-value, and state the conclusion of the test. $$ \begin{array}{lrrrr} \text { Analysis of Variance } & & & & \\ \text { Source } & \text { DF } & \text { SS } & \text { MS } & \text { F } & \text { P } \\ \text { Regression } & 1 & 3396.8 & 3396.8 & 21.85 & 0.000 \\ \text { Residual Error } & 174 & 27053.7 & 155.5 & & \\ \text { Total } & 175 & 30450.5 & & & \end{array} $$

Data 9.1 on page 577 introduces the dataset InkjetPrinters, which includes information on all-in-one printers. Two of the variables are Price (the price of the printer in dollars) and CostColor (average cost per page in cents for printing in color). Computer output for predicting the price from the cost of printing in color is shown: $$ \begin{aligned} &\text { The regression equation is Price }=378-18.6 \text { CostColor }\\\ &\begin{array}{lrrrrr} \text { Analysis of Variance } & & & & \\ \text { Source } & \text { DF } & \text { SS } & \text { MS } & \text { F } & \text { P } \\ \text { Regression } & 1 & 57604 & 57604 & 13.19 & 0.002 \\ \text { Residual Error } & 18 & 78633 & 4369 & & \\ \text { Total } & 19 & 136237 & & & \end{array} \end{aligned} $$ (a) What is the predicted price of a printer that costs 10 cents a page for color printing? (b) According to the model, does it tend to cost more or less (per page) to do color printing on a cheaper printer? (c) Use the information in the ANOVA table to determine the number of printers included in the dataset. (d) Use the information in the ANOVA table to compute and interpret \(R^{2}\). (e) Is the linear model effective at predicting the price of a printer? Use information from the computer output and state the conclusion in context.

The dataset OttawaSenators contains information on the number of points and the number of penalty minutes for 24 Ottawa Senators NHL hockey players. Computer output is shown for predicting the number of points from the number of penalty minutes: The regression equation is Points \(=29.53-0.113\) PenMins \(\begin{array}{lrrrr}\text { Predictor } & \text { Coef } & \text { SE Coef } & \text { T } & \text { P } \\ \text { Constant } & 29.53 & 7.06 & 4.18 & 0.000 \\ \text { PenMins } & -0.113 & 0.163 & -0.70 & 0.494\end{array}\) \(\mathrm{S}=21.2985 \quad \mathrm{R}-\mathrm{Sq}=2.15 \% \quad \mathrm{R}-\mathrm{Sq}(\mathrm{adj})=0.00 \%\) Analysis of Variance Source Regression Residual Error Total 2 \(\begin{array}{rrrrr}\text { DF } & \text { SS } & \text { MS } & \text { F } & \text { P } \\ 1 & 219.5 & 219.5 & 0.48 & 0.494 \\ 22 & 9979.8 & 453.6 & & \\ 23 & 10199.3 & & & \end{array}\) (a) Write down the equation of the least squares line and use it to predict the number of points for a player with 20 penalty minutes and for a player with 150 penalty minutes. (b) Interpret the slope of the regression equation in context. (c) Give the hypotheses, t-statistic, p-value, and conclusion of the t-test of the slope to determine whether penalty minutes is an effective predictor of number of points. (d) Give the hypotheses, F-statistic, p-value, and conclusion of the ANOVA test to determine whether the regression model is effective at predicting number of points. (e) How do the two p-values from parts (c) and (d) compare? (f) Interpret \(R^{2}\) for this model.

Golf Scores In a professional golf tournament the players participate in four rounds of golf and the player with the lowest score after all four rounds is the champion. How well does a player's performance in the first round of the tournament predict the final score? Table 9.6 shows the first round score and final score for a random sample of 20 golfers who made the cut in a recent Masters tournament. The data are also stored in MastersGolf. Computer output for a regression model to predict the final score from the first-round score is shown. Use values from this output to calculate and interpret the following. Show your work. (a) Find a \(95 \%\) interval to predict the average final score of all golfers whoshoot a 0 on the first round at the Masters. (b) Find a \(95 \%\) interval to predict the final score of a golfer who shoots a -5 in the first round at the Masters. (c) Find a \(95 \%\) interval to predict the average final score of all golfers who shoot a +3 in the first round at the Masters. The regression equation is Final \(=0.162+1.48\) First \(\begin{array}{lrrrr}\text { Predictor } & \text { Coef } & \text { SE Coef } & \text { T } & \text { P } \\ \text { Constant } & 0.1617 & 0.8173 & 0.20 & 0.845 \\ \text { First } & 1.4758 & 0.2618 & 5.64 & 0.000 \\ S=3.59805 & R-S q=63.8 \% & \text { R-Sq }(a d j) & =61.8 \%\end{array}\) Analysis of Variance Source Regression Residual Error Total \(\begin{array}{rrrrr}\text { DF } & \text { SS } & \text { MS } & \text { F } & \text { P } \\ 1 & 411.52 & 411.52 & 31.79 & 0.000 \\ 18 & 233.03 & 12.95 & & \\ 19 & 644.55 & & & \end{array}\)

Exercise 2.143 on page 102 introduces a study examining years playing football, brain size, and percentile score on a cognitive skills test. We show computer output below for a model to predict Cognition score based on Years playing football. (The scatterplot given in Exercise 2.143 allows us to proceed without serious concerns about the conditions.) Pearson correlation of Years and Cognition \(=-0.366\) P-Value \(=0.015\) Regression Equation Cognition \(=102.3-3.34\) Years Coefficients \(\begin{array}{lrrrr}\text { Term } & \text { Coef } & \text { SE Coef } & \text { T-Value } & \text { P-Value } \\ \text { Constant } & 102.3 & 15.6 & 6.56 & 0.000 \\ \text { Years } & -3.34 & 1.31 & -2.55 & 0.015 \\ & & & & \\ & \text { S } & \text { R-sq } & \text { R-sq(adj) } & \text { R-sq(pred) } \\ 25.4993 & 13.39 \% & 11.33 \% & 5.75 \%\end{array}\) Analysis of Variance \(\begin{array}{lrrrrr}\text { Source } & \text { DF } & \text { Adj SS } & \text { Adj MS } & \text { F-Value } & \text { P-Value } \\\ \text { Regression } & 1 & 4223 & 4223.2 & 6.50 & 0.015 \\ \text { Error } & 42 & 27309 & 650.2 & & \\ \text { Total } & 43 & 31532 & & & \\ & \-- & & & \end{array}\) (a) What is the correlation between these two variables? What is the p-value for testing the correlation? (b) What is the slope of the regression line to predict cognition score based on years playing football? What is the t-statistic for testing the slope? What is the p-value for the test? (c) The ANOVA table is given for testing the effectiveness of this model. What is the F-statistic for the test? What is the p-value? (d) What do you notice about the three p-values for the three tests in parts \((\mathrm{a}),(\mathrm{b}),\) and \((\mathrm{c}) ?\) (e) In every case, at a \(5 \%\) level, what is the conclusion of the test in terms of football and cognition?

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