Answer:
Step-by-step explanation:
First we need to find the total amount of apples in the crate:
Total = 10 + 14 + 4 + 18 = 46 apples
The probability of the first apple being a golden delicious apple is the number of those apples over the total number of apples:
Then, the probability of the second apple being a granny Smith apple is the number of those apples over the total number of apples, but now the total number of apples is one less, because one apple was removed from the crate:
The final probability we want is the product of those two probabilities:
To find this answer you simply subtract eight from sixty-two, which gives you....
54!
So there are 54 student in the science club!
Hope this helps! :)
Answer:
i) is correct answer i think
The question is incomplete! Complete question along with answer and step by step explanation is provided below.
Question:
The lifetime (in hours) of a 60-watt light bulb is a random variable that has a Normal distribution with σ = 30 hours. A random sample of 25 bulbs put on test produced a sample mean lifetime of = 1038 hours.
If in the study of the lifetime of 60-watt light bulbs it was desired to have a margin of error no larger than 6 hours with 99% confidence, how many randomly selected 60-watt light bulbs should be tested to achieve this result?
Given Information:
standard deviation = σ = 30 hours
confidence level = 99%
Margin of error = 6 hours
Required Information:
sample size = n = ?
Answer:
sample size = n ≈ 165
Step-by-step explanation:
We know that margin of error is given by
Margin of error = z*(σ/√n)
Where z is the corresponding confidence level score, σ is the standard deviation and n is the sample size
√n = z*σ/Margin of error
squaring both sides
n = (z*σ/Margin of error)²
For 99% confidence level the z-score is 2.576
n = (2.576*30/6)²
n = 164.73
since number of bulbs cannot be in fraction so rounding off yields
n ≈ 165
Therefore, a sample size of 165 bulbs is needed to ensure a margin of error not greater than 6 hours.
The solution for this problem is:
The population is 500 times bigger since 8000/24 = 500. The population after t days is computed by:P(t) = P₀·4^(t/49)
Solve for t: 8000 = 8·4^(t/49) 1000 = 4^(t/49) log₄(1000) = t/49t = 49log₄(1000) ≅ 244 days
