A bag contains 8 yellow marbles and 7 red marbles. What is the probability of pulling out a yellow marble?
1 answer:
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Answer:
95% of monthly food expenditures are between $110 and $190.
Step-by-step explanation:
Given : The monthly amounts spent for food by families of four receiving food stamps approximates a symmetrical, normal distribution. The sample mean is $150 and the standard deviation is $20.
To find : Using the Empirical rule, about 95% of the monthly food expenditures are between which of the following two amounts?
Solution :
At 95% of the data is between two standard deviation to left and right of the mean is given by,
To the left side,
To the right side,
We have given,
The sample mean
The standard deviation
Substitute in the formula,
Therefore, 95% of monthly food expenditures are between $110 and $190.
So we are given the expression:
÷
When we divide fractions, we must flip the second term and change the sign to multiplication:
And then we multiply across:
Then we can break apart all of the like variables for simplification:
When we simplify variables through division, we subtract the exponent of the numerator from the exponent of the denominator. So we then have:
So then we multiply all of these simplified parts together:
So now we know that the simplified form of the initial expression is: .