Entomologist heinz kaefer has a colony of bongo spiders in his lab. there are 1000 adult spiders in the colony, and their weight
s are normally distributed with mean 11 grams and standard deviation 2 grams. about how many spiders are there in the colony which weigh more than 12 grams?
The probability that a spider selected at a random from the colony weighs more than 12 grams is given by:
Thus, given that there are 1000 adult spiders in the colony, the number of spiders in the colony that weigh more than 12 grams is given by 0.30854 * 1000 ≈ 309
We have to find the probability N(11,2)>12, wherein N(11,2) is the normal law with mean 11 and standard deviation 2. Using a scientific calculator we get the probability 0.3.
Now multiply by the population which is 1000 like this: 0.3*1000=300.
There is 300 <span>spiders in the colony which weigh more than 12 grams</span>
The shading is below the line so it is y ≤ and then the slope is -1/3x because when you go down 1 and 3 units to the right, you get another point. And lastly, the y-intercept is 1.