6.665 grams of the 13 grams remain after 8 hours.
<h3>How much of a 13 gram sample of iron-52 would remain after 8 hours?</h3>
The decay equation for the 13 grams of iron-52 is:

Where N is the amount of iron-52, and t is the time in years.
Where we used the fact that the half-life is exactly 8.3 hours.
Now, the amount that is left is given by N(8h), so we just need to replace the variable t by by 8 hours, so we get:

So 6.665 grams of the 13 grams remain after 8 hours.
If you want to learn more about half-life:
brainly.com/question/11152793
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Answer:
The standard deviation reduces when sample size (n) increases
Step-by-step explanation:
From the above information given, we have that mean = 75.5
Standard deviation = 3.5
But Standard deviation = √summation (x-u)/n
This simply implies that when sample (n) is increased there would be a reduction in the standard deviate.
Step-by-step explanation:
114° thats what i got when i calculated
Answer : 0.0129
Step-by-step explanation:
Given : Based on FAA estimates the average age of the fleets of the 10 largest U.S. commercial passenger carriers is
years and standard deviation is
years.
Sample size : 
Let X be the random variable that represents the age of fleets.
We assume that the ages of the fleets of the 10 largest U.S. commercial passenger carriers are normally distributed.
For z-score,

For x=14

By using the standard normal distribution table , the probability that the average age of these 40 airplanes is at least 14 years old will be :-

Hence, the required probability = 0.0129
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