Dataset exercise
By: Juan J. Ruiz-Rojas
01-24-2007
1) Evaluation of the number of F1 GFP positive plants obtained from
three transgenic lines of Strawberry (Fragaria vesca)
2) Variables and their statistical properties
Variable
Type of variable
Role
Number of
Quantitative
Response
GFP+ plants
(Ratio)
(1..20)
Fragaria vesca
Qualitative
Explenatory
lines (FV-358,
(nominal)
FV-359, FV360)
label
Random
Nonrandom
3) Research strategy: experimental. We use three strawberries lines as
experimental units.
4) We evaluated F1 population from three transgenic strawberries lines
to identify the number of Green Fluorescence Protein (GFP) positive
plants per line. For each line five fruits were collected to generate F1
population and seedlings were screen for GFP presence.
5) JMP data table
Fragaria vesca
(lines, 358,359,360)
FV-358
FV-359
FV-360
FV-358
FV-359
FV-360
FV-358
FV-359
FV-360
FV-358
FV-359
FV-360
FV-358
FV-359
FV-360
Transgenic Plants
(GFP +)
18
4
10
14
8
8
20
8
6
17
9
5
12
7
4
6) Summary Table
N Rows
N
(FV
lines)
FV-358
5
5
5
16.2
3.19
10.2
1.43
FV-359
5
5
5
7.2
1.92
3.7
0.86
FV-360
5
5
5
6.6
2.41
5.8
1.08
FV lines
N
(Plants
GFP +)
Mean
(Plants
GFP +)
Std Dev
(Plants
GFP +)
Variance
(Plants
GFP +)
Std Err
(Plants
GFP +)
7- f) Explain the similarities, differences, and relationships among the
statistics standard error, standard deviation, and variance (What aspect-location, dispersion, or shape--of the data do they describe, what type of
variable do they apply to, and how do they differ? Specifically, answer
these questions for each of the three statistics:
The standard error is the estimated standard deviation of a statistic. The
standard error of a sample mean is just the sample standard deviation
divided by the square root of the sample size. The standard error of a rate
is a measure of the sampling variability of the rate
The standard deviation is kind of the "mean of the mean," a measure of
the dispersion of a set of data from its mean. The more spread apart the
data is, the higher the deviation. Also, Standard deviation is a statistical
measure of spread or variability, statistical measure of dispersion: a
statistical measure of the amount by which a set of values differs from
the arithmetical mean, equal to the square root of the mean of the
differences' squares
The variance is a measure of its statistical dispersion, indicating how far
from the expected value its values typically are. A measure of the average
distance between each of a set of data points and their mean value; equal
to the sum of the squares of the deviation from the mean value. The
variance of a distribution is the average of squares of the distances from
the values drawn from the mean of the distribution
The variance expresses the same type of information as does standard
deviation, but it has certain very important properties relative to
probability and hypothesis testing that make it distinctly superior, also
the variance has square units. The standard deviation is the positive
square root of the variance
The standard error of a statistic is refereed also as a standard deviation;
it has significant importance in hypothesis testing and related
procedures
i- Does the statistic measure (a) location, (b) dispersion, (c) or shape?
Standard deviation, measure dispersion
ii- Whatever it measures, does it measure it for (a) qualitative categorical
variables, or (b) quantitative measurement variables?
Standard error, measure quantitative measurement variables
iii- Whatever it measures, does it measure it for (a) the underlying
random variable of interest, or (b) the sample mean? ).
Variance, measure for the underlying random variable of interest
8) Do you believe there is a statistically significant difference among
the group means you tabulated? Why or why not?
According with the means that I have calculated, there is a big difference
between FV-358 lines (mean 16.2) to FV-359 (7.2) and FV-360 (6.6) lines.
The average of plants GFP+ from line FV-358 is more than two times
bigger than the average of FV-359 and FV-360, also the variance is two
times bigger than the others lines, showing that FV-358 line has either
significant statistical progress or good genetically qualities among these
lines. Moreover, between lines FV-359 and FV-360, there is not
difference, as we can see in the summary table.
9) Do you believe there is a biologically important difference among the
means you tabulated? Why or why not?
There is a biological important difference in this experiment, because we
have detected a big amount of transgenic plants in one of three lines
evaluated. It means that the plant transformation protocol for
strawberries works better in the line FV-358 because we have been
detected a bigger number of transgenic GFP+ plants. Besides, lines FV359 and FV-360, are lines that have almost the same mean, and we can
predict that there is not necessary to include both of then for future
experiments as a control for low level of plant transformation and GFP
expression. Finally, future experiments can be conducted using this
information as a support for improvement strawberry genomics studies