The teacher would have to grade 322 problems
14 (problems) x 23 (students)
Answer: 322
You're going to have to work out the z-scores of both values in each option and see if it makes sense.
n = m + sz
The mean is 20 and the standard deviation is 3.
So let's find try the z-scores of the outer range values and determine their probabilities:
from 14-20:
n = m + sz
20 = 20 + 3z and 14 = 20 + 3z
0 = 3z and -6 = 3z
z = 0 and z = -2
So now using a z-score table, such as the one below, find the probabilities.
z = 0 is easy, it's 0.5
z = -2 is 0.02275
Subtract the smaller from the larger to get the probability of getting in the range:
0.5 - 0.02275 = 0.47725 (so times 1000, you get 477.25, which is not about 340, so this option is wrong)
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Now trying option 2, from 17-29:
n = m + sz
29 = 20 + 3z and 17 = 20 + 3z
9 = 3z and -3 = 3z
z = 3 and z = -1
0.99865 - 0.158655 = 0.839995 (not 680, so not the answer)
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Now trying option 3, from 20-23:
n = m + sz
23 = 20 + 3z and 20 = 20 + 3z
3 = 3z and 0 = 3z
z = 1 and z = 0
0.841345 - 0.5 = 0.341345 (close to 340, so is your answer)
Answer:
Survey 100 residents who have pets completely randomly
Step-by-step explanation:
The best sampling method would be to Survey 100 residents who have pets completely randomly. This would provide first-hand information from actual pet owners which would make the results valid. Also, by choosing the individuals to survey completely randomly it allows for the data to be unbiased and representative of the entire pet owner population in the city. This makes the data gathered completely unbiased and valid.
Answer:9
Step-by-step explanation:
45/5 =9
s=d/t