Answer:
68% of the sample can be expected to fall between 28 and 32 cm
Step-by-step explanation:
The Empirical Rule states that, for a normally distributed random variable:
68% of the measures are within 1 standard deviation of the mean.
95% of the measures are within 2 standard deviation of the mean.
99.7% of the measures are within 3 standard deviations of the mean.
In this problem, we have that:
Mean = 30
Standard deviation = 2
What proportion of the sample can be expected to fall between 28 and 32 cm
28 = 30-2
28 is one standard deviation below the mean
32 = 30 + 2
32 is one standard deviation above the mean
By the Empirical Rule, 68% of the sample can be expected to fall between 28 and 32 cm
C.
12/30=0.4
You should really learn how to do probabilities. They don't go away after like the sixth grade.
8.25% of 55.60 = 4.58700
We round that number to 4.59
(I am assuming the tip is based on the amount of the pretax bill.)
15% of 55.60 = 8.34
So $55.60 + $4.59 + 8.34 = $68.53
The bill would be $68.53.
