Two point estimates am i correct

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In summary, the conversation discusses a concentration calculation for a cocaine sample using two-point determination. The general equation Y = mx + c is used, with two standard equations and an unknown equation. After solving for m and c, the final formula is Y = 461821.62 X + 6132. However, a correction is made for significant figures, resulting in a final concentration of 6%. The individual is thanked for their help and pointers.
  • #1
Scarpetta
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Can anyone tell me if this concentration calculation is correct please, its my first attempt and a bit unsure.
Two point determination of cocaine sample
Cocaine (mg/ml) Average peak height
0.015 13059
0.20 98496
Unknown (2mg/ml) 61136
General equation Y = mx + c
Equation 1 standard 1: 13059 = 0.015m + c
Equation 2 standard 2: 98496 = 0.20m + c
98496 – 13059 = 85437
0.20 – 0.015 = 0.185
therefore 85437 = 0.185m + 0
85437 / 0.185 = m
m = 461821.62
c = 13059 = (0.015 X 461821.62)
13059 – (0.015 X 461821.62) = 6132
So, Y = 461821.62 X + 6132
Unknown therefore:
61136 = 461821.62 X + 0
= 61136 – 0 / 461821.62 = 0.13
0.13 / 2 X 100 = 6.6%
 
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  • #2
Scarpetta said:
So, Y = 461821.62 X + 6132
Unknown therefore:
61136 = 461821.62 X + 0
= 61136 – 0 / 461821.62 = 0.13
0.13 / 2 X 100 = 6.6%

Why? You just determed that c is 6132. Following your logic it should be
61136 = 461821.62 X + 6132

0.20 – 0.015 = 0.19 <-- here you have only 2 significant figures.
therefore 85437 = 0.19m
85437 / 0.19 = m = 450000

Hence 61136 = 450000*x + 6132
55004 = 450000*x , x = 0.12
0.12/2 = 0.06 = 6%
 
  • #3
not bad for a first attempt, close but no cigar, thankx for the pointers
 

1. What are two point estimates?

Two point estimates refer to two numerical values that are used to estimate a population parameter. These values are typically calculated from a sample of data and are used to make inferences about the larger population.

2. How are two point estimates calculated?

Two point estimates are calculated by taking two values from a sample of data and using them to make predictions about the larger population. These values can be the mean, median, or any other measure of central tendency.

3. What is the purpose of using two point estimates?

The purpose of using two point estimates is to provide a range of values for a population parameter, rather than a single point estimate. This allows for a more accurate representation of the population and takes into account any potential variability in the data.

4. How do you determine which two values to use for a two point estimate?

The two values used for a two point estimate should be chosen based on their relevance and representativeness of the larger population. They should also be based on the specific research question and the type of data being analyzed.

5. Can two point estimates be used for any type of data?

Yes, two point estimates can be used for any type of data as long as the values chosen are appropriate for the research question and accurately represent the larger population. However, they may not always be the most suitable method and other types of estimates, such as confidence intervals, may be more appropriate in certain situations.

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