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Zolol [24]
3 years ago
14

Please help, I’m unsure how to do standard deviation so I’m very confused!

Mathematics
1 answer:
lidiya [134]3 years ago
6 0

a. With an average/mean of 7 dreams, one standard deviation away from the mean corresponds to the interval [7 - 1.7, 7 + 1.7] = [5.3, 8.7]. So children within one standard deviation of the mean experience somewhere between 5 and 9 dreams. Two standard deviations from the mean refers to the interval [7 - 2 * 1.7, 7 + 2 * 1.7] = [3.6, 10.4]. So children in this range have between 3.6 and 10.4 dreams.

b. We already know that the interval [5.3, 8.7] is one standard deviation from the mean. If we assume the number of dreams is normally distributed with mean 7 and standard deviation 1.7, then we can apply the empirical rule (a.k.a. 68-95-99.7), which says that for any normal distribution, roughly 68% of the distribution falls within one standard deviation of the mean. So we can expect roughly 68% of the 4800 children to have between 5.3 and 8.7 dreams, or about 3264 students.

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Answer:

0.665

Step-by-step explanation:

Given:  100 people are split into two groups 70 and 30.  I group is given cough syrup treatment but second group did not.

Prob for a person to be in the cough medication group = 0.70

Out of people who received medication, 34% did not have cough

Prob for a person to be in cough medication and did not have cough

=\frac{0.70(34)}{60}=0.397


Prob for a person to be not in cough medication and did not have cough

=\frac{0.3(20)}{30}=0.20

Probability for a person not to have cough

= P(M1C')+P(M2C')

where M1 = event of having medication and M2 = not having medication and C' not having cough

This is because M1 and M2 are mutually exclusive and exhaustive

SO P(C') = 0.397+0.2=0.597

Hence required prob =P(M1/C') = \frac{0.397}{0.597}=0.665

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Use the following information to answer problems 14-16: Suppose that in a large metropolitan area, 82% of all households have ca
Helen [10]

Answer:

66.6% or 0.66

Step-by-step explanation:

82% or 0.82 of All households have cable TV.

X = The number of households in a group of 6, that have cable TV.

You wish to find the proportion or percentage of groups for which EXACTLY 4 of 6 households will have cable TV.

82% of 6 is = 4.92

Approximately 4.92 out of 6 households, have cable TV.

Using this figure, you can now find out what % of 6 will give you 4.

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M = (4×0.82) ÷ 4.92 = 3.28÷4.92 = 0.666

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Rainbow [258]

Answer:

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Step-by-step explanation:

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