Biology Reference
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(a) Print the column names.
(b) Print the range and the quartiles of each variable.
(c) Print all the observations for which A falls in the interval
[
3
,
4
]
and B in
.
(d) Sample 50 rows without replacement.
(e) Draw a bootstrap sample (e.g., sample 5
( ,−
5
] [
10
, )
,
000 observations with replacement)
and compute the mean of each variable.
(f) Standardize each variable.
1.6. Generate a data frame with 100 observations for the following variables:
(a) A categorical variable with two levels, low and high . The first 50 observations
should be set to low , the others to high .
(b) A categorical variable with two levels, good and bad , nested within the first
variable, i.e., the first 25 observations should be set to good , the second 25 to
bad , and so on.
(c) A continuous, numerical variable following a Gaussian distribution with mean
2 and variance 4 when the first variable is equal to low and with mean 4 and
variance 1 if the first variable is equal to high .
In addition, compute the standard deviation of the last variable for each configura-
tion of the first two variables.
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