2. Error Analysis: How accurate is your straight line? a. Examine your graph. Do most of your points fall on the best fit line, or are there outliers? b. The R² value is a measure of how close your experimental values match the corresponding values from the straight line. If R²>0.95, this indicates the straight line is a good approximation of your data. If R² <0.95, then then the line is not a good approximation of your data. Discuss how good your fit is based on the R² value.

Chemistry
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## Error Analysis: How Accurate is Your Straight Line?

### a. Examine Your Graph
- Do most of your points fall on the best-fit line, or are there outliers?

### b. Understanding \( R^2 \) Value
- The \( R^2 \) value measures how closely your experimental values match the corresponding values from the straight line. 
- If \( R^2 > 0.95 \), this indicates the straight line is a good approximation of your data. 
- If \( R^2 < 0.95 \), the line is not a good approximation of your data.
- Discuss how good your fit is based on the \( R^2 \) value.
Transcribed Image Text:## Error Analysis: How Accurate is Your Straight Line? ### a. Examine Your Graph - Do most of your points fall on the best-fit line, or are there outliers? ### b. Understanding \( R^2 \) Value - The \( R^2 \) value measures how closely your experimental values match the corresponding values from the straight line. - If \( R^2 > 0.95 \), this indicates the straight line is a good approximation of your data. - If \( R^2 < 0.95 \), the line is not a good approximation of your data. - Discuss how good your fit is based on the \( R^2 \) value.
**Instructions:**

1. Construct a standard curve in Excel by plotting concentration (in ppm) on your x-axis and absorbance (unitless) on your y-axis for your known solutions. Label the axes on the graph and provide a title. See Figure 5 in the lab handout for an example. Use a linear trendline to generate an equation from your data. Label the graph with the equation and the R² value. Insert your labeled graph in the report.

2. Using the equation from your graph, determine the nitrate concentration (in ppm) in each of your unknown samples.

**Graph Description:**

Title: Nitrate Standard Curve

- The graph plots "Concentration" on the x-axis (ranging from 0 to 7) and "Absorbance" on the y-axis (ranging from 0.5 to 5).
- A series of data points are plotted and a linear trendline has been added. 
- The equation of the line is provided: \( y = 0.8842x - 0.8191 \).
- The R² value, which indicates the goodness of fit for the trendline, is 0.9509. 

This graph is used to determine unknown nitrate concentrations using the equation provided.
Transcribed Image Text:**Instructions:** 1. Construct a standard curve in Excel by plotting concentration (in ppm) on your x-axis and absorbance (unitless) on your y-axis for your known solutions. Label the axes on the graph and provide a title. See Figure 5 in the lab handout for an example. Use a linear trendline to generate an equation from your data. Label the graph with the equation and the R² value. Insert your labeled graph in the report. 2. Using the equation from your graph, determine the nitrate concentration (in ppm) in each of your unknown samples. **Graph Description:** Title: Nitrate Standard Curve - The graph plots "Concentration" on the x-axis (ranging from 0 to 7) and "Absorbance" on the y-axis (ranging from 0.5 to 5). - A series of data points are plotted and a linear trendline has been added. - The equation of the line is provided: \( y = 0.8842x - 0.8191 \). - The R² value, which indicates the goodness of fit for the trendline, is 0.9509. This graph is used to determine unknown nitrate concentrations using the equation provided.
Expert Solution
Step 1: Analysis of straight line plot

The given case represents the analysis of the relationship between concentration and absorbance of a substance graphically. A plot of concentration and absorbance must be a straight line.

A straight line that best fits with the experimentally collected data is drawn. The R2 value indicates the accuracy of the graph with the collected values.

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