4.The presence of any chemical reactions
5.Changes in color localized to the organism or the
surrounding
media
6.Capture (or draw) images of any of the characteristics
described
above
Question 3
10 / 10 pts
While observing an unknown sample of limited amounts,
a researcher must determine
the following observations: (1) the presence of any
motility and (2) its Gram status using
the same sample—the liquid sample cannot be divided.
Which would you determine first
and why?
Your Answer:
You would need to determine the motility before gram
status. You can observe motility
on a wet mount and then heat fix your sample to gram
stain your sample. If you were to
begin with using gra
1. ASuppose that you are attempting to estimate the
weight of 600 parts. In order to use the infinite
standard deviation formula, what sample size, n,
should you use?
n≤0.05(1200) n≤60
So, the sample size should be less than 60.
2. Suppose that you are attempting to estimate the
annual
income of 2000 families. In order to use the infinite
standard deviation formula, what sample size, n, should
you use?In order to use infinite standard deviation
formula, we should have:
n≤0.05(2000) n≤100
So, the sample size should be less than 100.
2. Suppose that you take a sample of size 15 from a
population that is known to be normally distributed.
Can the sampling distribution of be approximated
by a normal probability distribution? Yes, the
sampling distribution of can be approximated by a
normal probability distribution because the
population is normally distributed. (Recall that if the
population is normally distributed, the sampling
distribution of can be approximated by a normal
probability distribution even for very small sample
sizes.)
3. Suppose that you take a sample of size 20 from a
population that is not normally distributed. Can the
sampling distribution of be approximated by a
normal probability distribution? No, the sampling
distribution of cannot be approximated by a
normal probability distribution in this case. (Recall
that if the population is not normally distributed, the
sample size must be at least 30.) No. The
population is not normally distributed, therefore, we
need a sample size of at least 30 to approximate by
a normal probability distribution.
Question:
4. Suppose that in a large hospital system, that the
average (mean) time that it takes for a nurse to take the
temperature and blood pressure of a patient is 180
seconds with a standard deviation of 55 seconds. What is
the probability that 30 nurses selected at random will
have a mean time of 150 seconds or less to take the
temperature and blood
pressure of a patient?
We calculate the standard deviation of the sample
distribution:
Calculate the z-score:
So, we want to find P(Z < -2.99) on the standard normal
probability distribution table. Recall that
P(Z < -2.99) = .00139.
Therefore, there is a 0.00139 probability that a simple
random sample of 30 nurses will have a mean time of 150
seconds or less.
QUESTION 4
Suppose that in a large hospital system, that the average
(mean) time that it takes for a nurse to take the
temperature and blood pressure of a patient is 170
seconds with a standard deviation of 40 seconds. What is
the probability that 20 nurses selected at random will
havea mean time of 165 seconds or less to take the
temperature and blood pressure of a patient?
We calculate the standard deviation of the sample
distribution:
40/SQRT 20=8.944
