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Hello,

please comple these 4 lab question for me below. I have attached the document needed for this assignment. The worksheet and the lab information.

BIOL2O2
Measurement Lab
Part I - What are averages and standard deviations?
Many physiological parameters are measured and compared to the “normal” value in order
to determine if you are within the normal range. For example, doctors often measure a
child’s length and weight during the several months after it is born to determine if the child
has normal or abnormal growth. The question is how are these “normal” values obtained?
Averages and Standard deviation
The average of several values is simply the total divided by the number of samples.
Standard deviation is a calculation that allows statisticians to determine how much number
can vary from the average and still be considered within range of normal.
One standard deviation from an average with normal variation generally includes 68% of
the population, while two standard deviations from the average include 95% of the
population. For example, the average IQ is about 110±10. That means that average is 110
and the standard deviation is 10. Therefore, 68% of people are between 100 and 120 and
95% of people are between 90 and 130.
Often standard deviation is shown on TV when reporting polls. For example, you might
have seen that “45% of people agree with this statement and 55% disagree with a 3% error”.
This means that the poll represents the entire population of people and 42-48% agree and
52-58% disagree.
Standard deviation calculations are more powerful with a larger sample size and would be
completely accurate if the entire population was used as the sample. However, it is
impossible to measure every single person’s pulse in this class. The average may be
different if we measured 100 people compared to the number of students in this class.
Standard deviation is calculated using the following formula:
x x 2
SD
n 1
n = number of data values in the sample
x = value of each data point
x = mean
Steps
(1) Calculate the mean (average =x)
(2) Subtract the mean from each x value
(3) Square each ( x - x ) value
(4) Add all these squared values together this value is called the sum of squares (SS).
(5) Calculate n-1 where (n - 1 ) is one less than the total number of data values in the
sample
(6) Divide the SS by n-1
(7) Calculate the square root of the number that you get from step 6
Part II: Using standard deviations to determine accuracy
Standard deviation has another use, to measure accuracy. Some devices are more accurate
than others when it comes to measuring physiological parameters or any parameter. For
example using a yard stick to measure the length of a table would not be as accurate as
using a tape measure because the table is longer than a yard stick. The length of the table
is the same regardless of how you measure it but the measuring tape would be more
accurate.
Watch the video for a demonstration of the activity mentioned below:
This exercise will compare accuracy of measurement. Using the pipettes and graduated
cylinders, add 40ml of water to your WEIGHED beaker using the following volume
amounts. Weigh your beaker after each attempt.
Attempt#1 (Use pipette)
4.0 ml
5.0 ml
4.5 ml
2.5 ml
4.5 ml
5.0 ml
3.5 ml
5.0 ml
3.5 ml
2.5 ml
Attempt #2 (use graduated cylinder)
40 ml
Attempt #3 (use graduated cylinder)
20 ml
20 ml
Attempt #4 (use beaker to measure)
40 ml
Now record the weight of the water (remember to subtract the weight of the empty beaker)
of each attempt. Convert the weight of the water to volume of water by using the density
of water, which is 0.998 g/ml. Divide the weight of the water by the density of water to
determine the volume of water in the beaker. Record your values, then determine the class
average and standard deviation.
Data from the above experiment performed by six teams is provided at the end of
the video. Use this data to calculate the averages and standard deviations for the
attempts.
Based on this analyzed data answer the questions in the work sheet.
BIOL202
Measurement Lab
Student Work sheet
Name:
Attempt #1:
Class average ___________ Std. Dev,________
Attempt #2:
Class average ___________ Std. Dev. _______
Attempt #3:
Class average ___________ Std. Dev. ________
Attempt #4:
Class average ___________ Std. Dev. ________
1. Which attempt gave the closest value to 40? Was that expected? Why or why not?
2. Which had the smallest standard deviation? Was this expected? Why or why not?
3. Which method was accurate to measure out 40 ml of water?
BIOL202
Measurement Lab
Student Work sheet
Name:
Attempt #1:
Class average ___________ Std. Dev,________
Attempt #2:
Class average ___________ Std. Dev. _______
Attempt #3:
Class average ___________ Std. Dev. ________
Attempt #4:
Class average ___________ Std. Dev. ________
1. Which attempt gave the closest value to 40? Was that expected? Why or why not?
2. Which had the smallest standard deviation? Was this expected? Why or why not?
3. Which method was accurate to measure out 40 ml of water?
4. What are some sources of error in this experiment?
...

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