28) If 60% of A is 30% of B, then B is what percent of A?
2 answers:
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We cannot calculate the confidence interval without the sample size. However, for the second question, the sample size needed would be 49.
The formula we use is
To find the z-score:
Convert 98% to a decimal: 0.98
Subtract from 1: 1-0.98 = 0.02
Divide by 2: 0.02/2 = 0.01
Subtract from 1: 1-0.01 = 0.99
Using a z-table (http://www.z-table.com) we see that this value is closest to a z-score of 2.33.
Using the z-score, our standard deviation (9) and our margin of error (3), we have:
The formula we use is
To find the z-score:
Convert 98% to a decimal: 0.98
Subtract from 1: 1-0.98 = 0.02
Divide by 2: 0.02/2 = 0.01
Subtract from 1: 1-0.01 = 0.99
Using a z-table (http://www.z-table.com) we see that this value is closest to a z-score of 2.33.
Using the z-score, our standard deviation (9) and our margin of error (3), we have:
Answer and explanation:
Given : Strands Copper wire from a manufacturer are analyzed forstrenghth and conductivity. The Results from 100 strands are as follows :
Strength Strength
High Low
High conductivity 74 8
Low conductivity 15 3
To find :
a) If a stand is randomly selected, the probability that is conductivity is high and its strength is high
The favorable outcome is 74
The probability is given by,
b) If a stand is randomly selected, the probability that its conductivity is low or strength is low
Conductivity is low A= 15+3=18
Strength is low B= 8+3=11
Conductivity is low and strength is low
Probability is given by,
c) Consider the event that a strand low conductivity and the event that the strand has a low strength. Are these tow events mutually exclusive?
Since the events the stand has low conductivity and the stand has low strength are not mutually exclusive, since there exists some cases in which both the events coincide. i.e. Intersection of both the events exists with probability 0.03.