Calculating probability from linear regression parameters

In summary, to calculate the probability in part b from the linear regression parameters, you need to use the equation Y = β0 + β1X + ε, where ε ~ N(0, σ^2). Make sure to use the squared variance, σ^2, and not the standard deviation, σ. This will give you the probability of Y taking on a specific value when X is equal to 40. You can also use this equation to calculate the probability for a range of values by taking the integral of the normal distribution over that range.
  • #1
sadfe
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Screenshot 2021-05-25 at 02.28.24.png


I'm a bit stuck on how to calculate the probability in part b from the linear regression parameters.
I tried plugging the parameter values into the linear regression model: Y =β0+β1X+ε, ε∼N(0,σ)
So P(Y=y| X=40) = 2.85 + 0.07 * 40 + 1^2
P(Y=y|X=40) = 5.65
But I don't think this is the value I want. Any ideas where I'm going wrong?
 
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  • #2


Hi there,

It looks like you are on the right track with plugging in the parameter values into the linear regression model. However, the equation you are using is not quite correct. The correct equation for the linear regression model is: Y = β0 + β1X + ε, where ε ~ N(0, σ^2). Notice that the variance, σ^2, is squared, not the standard deviation, σ.

So, the correct equation for calculating the probability would be: P(Y=y| X=40) = β0 + β1(40) + ε, where ε ~ N(0, σ^2). This would give you the probability of Y taking on a specific value, y, when X is equal to 40. You can also use this equation to calculate the probability for a range of values by taking the integral of the normal distribution over that range.

I hope this helps clarify things for you. Let me know if you have any further questions. Good luck with your calculations!
 

1. How do I calculate the probability from linear regression parameters?

To calculate the probability from linear regression parameters, you can use the formula for the cumulative distribution function (CDF) of the normal distribution. This formula takes into account the mean and standard deviation of the data, as well as the specific value you are interested in. You can also use statistical software or online calculators to perform this calculation.

2. Can I use linear regression to predict probabilities?

Yes, linear regression can be used to predict probabilities. This is because linear regression models the relationship between a continuous dependent variable and one or more independent variables. By using this relationship, you can estimate the probability of a certain outcome occurring based on the values of the independent variables.

3. How accurate are the probability estimates from linear regression?

The accuracy of probability estimates from linear regression depends on various factors, such as the quality and quantity of the data, the assumptions of the model, and potential confounding variables. It is important to assess the goodness of fit of the regression model and consider the uncertainty associated with the estimates when interpreting the results.

4. Can I use linear regression to calculate conditional probabilities?

Yes, linear regression can be used to calculate conditional probabilities. This can be done by including the relevant independent variables in the regression model and interpreting the coefficients as the effect of these variables on the probability of the outcome occurring.

5. Are there any limitations to using linear regression for calculating probabilities?

Yes, there are some limitations to using linear regression for calculating probabilities. For example, linear regression assumes a linear relationship between the dependent and independent variables, which may not always hold true. Additionally, it may not be suitable for non-continuous outcomes or when there are non-linear relationships between the variables. It is important to consider the assumptions and limitations of the model when interpreting the results.

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