40 students are going on a field trip to the aquarium. Every student needs to be in a group, and all groups must have the same n
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Answer:
There is an 85.5% probability that both stages meet specifications.
Step-by-step explanation:
We have these following probabilities:
A 90% probability that the first stage meets specifications.
If the first stage meets specifications, a 95% probability that the second stage also meets specifications.
What is the probability that both stages meet specifications?
This is the multiplication of these probabilities. So:
There is an 85.5% probability that both stages meet specifications.
Total number of tables in the cafeteria = 20
65% of the tables =
= 13
Each table has 6 chairs.
So, total number of chairs that 65% of the tables have = 13 × 6 = 78.
35% of the tables =
= 7
Each table has 4 chairs.
So, total number of chairs that the remaining 35% of the tables have = 7 × 4 = 28.
Hence, total number of chairs in the hospital cafeteria = 78 + 28 = 106.
A sample size of 60 is required.
We use the formula
We first find the z-score associated with this level of confidence:
Convert 99% to a decimal: 99/100 = 0.99
Subtract from 1: 1-0.99 = 0.01
Divide by 2: 0.01/2 = 0.005
Subtract from 1: 1-0.005 = 0.995
Using a z-table (http://www.z-table.com) we see that this value is equally distant from 2.57 and 2.58; therefore we will use 2.575:
We use the formula
We first find the z-score associated with this level of confidence:
Convert 99% to a decimal: 99/100 = 0.99
Subtract from 1: 1-0.99 = 0.01
Divide by 2: 0.01/2 = 0.005
Subtract from 1: 1-0.005 = 0.995
Using a z-table (http://www.z-table.com) we see that this value is equally distant from 2.57 and 2.58; therefore we will use 2.575: