Answer:
Option A. 5.25 units
Step-by-step explanation:
we know that
If two figures are similar, then the ratio of its corresponding sides is proportional and its corresponding angles are congruent
so
substitute the given values
solve for XZ
Make up your own multiplication and division problem and solve them
1 answer:
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Answer:
(a) 0.2650
(b) 0.0111
(c) 0.0105
(d) 0.0006
Step-by-step explanation:
Given that:
In microbiology, colony-forming units (CFUs) are used to measure the number of microorganisms present in a sample.
Suppose that the number of CFUs that appear after incubation follows a Poisson distribution with mean μ = 15. &;
If the area of the agar plate is 75cm²;
what is the probability of observing fewer than 4 CFUs in a 25 cm² area of the plate.
We can determine the mean number of CFUs that appear on a 25cm² area of the plate as follows;
75cm²/25cm² = 3
Since;
mean μ = 15
mean number of CFUs that appear on a 25cm² = 15/3 = 5 CFUs
Thus ; the probability of observing fewer than 4 CFUs in a 25 cm² area of the plate is estimated as:
= P(X < 4)
Using the EXCEL FUNCTION ( = poisson.dist(3, 5, TRUE) )
we have ;
P(X < 4) = 0.2650
b) If you were to count the total number of CFUs in 5 plates, what is the probability you would observe more than 95 CFUs?
Given that the total number of CFUs = 5 plates; then the mean number of CFUs in 5 plates = 15×5 = 75 CFUs
The probability is therefore = P( X > 95 )
= 1 - P(X ≤ 95)
= 1 - poisson.dist(95,75,TRUE) ( by using the excel function)
= 0.0111
c) Repeat the probability calculation in part (b) but now use the normal approximation.
Let assume that the mean and the variance of the poisson distribution are equal
Then;
We are to repeated the probability calculation in part (b) from above;
So:
P( X > 95 )
use the normal approximation
From standard normal variable table:
P(Z > 2.3094)
Using normal table
P(Z > 2.3094) = 0.0105
(d) Find the difference between this value and your answer in part (b).
So;
the difference between the value in part c and part b is;
= 0.0111 - 0.0105
= 0.0006 to four decimal places